diff --git a/Ably.xcodeproj/project.pbxproj b/Ably.xcodeproj/project.pbxproj
index 83b9d451d..d0aec78ec 100644
--- a/Ably.xcodeproj/project.pbxproj
+++ b/Ably.xcodeproj/project.pbxproj
@@ -284,12 +284,21 @@
 		80E519C72BBCBE21006545B4 /* PrivacyInfo.xcprivacy in Resources */ = {isa = PBXBuildFile; fileRef = 80E519C62BBCBE20006545B4 /* PrivacyInfo.xcprivacy */; };
 		80E519C82BBCBE21006545B4 /* PrivacyInfo.xcprivacy in Resources */ = {isa = PBXBuildFile; fileRef = 80E519C62BBCBE20006545B4 /* PrivacyInfo.xcprivacy */; };
 		80E519C92BBCBE21006545B4 /* PrivacyInfo.xcprivacy in Resources */ = {isa = PBXBuildFile; fileRef = 80E519C62BBCBE20006545B4 /* PrivacyInfo.xcprivacy */; };
+		84039A4C2C811F49001C053E /* ARTChannelOptions+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 84039A4B2C811F49001C053E /* ARTChannelOptions+Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		84039A4D2C811F49001C053E /* ARTChannelOptions+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 84039A4B2C811F49001C053E /* ARTChannelOptions+Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		84039A4E2C811F49001C053E /* ARTChannelOptions+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 84039A4B2C811F49001C053E /* ARTChannelOptions+Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		840FCE532C875B8A001163E1 /* ARTDevicePushDetails+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 840FCE522C875B8A001163E1 /* ARTDevicePushDetails+Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		840FCE542C875B8A001163E1 /* ARTDevicePushDetails+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 840FCE522C875B8A001163E1 /* ARTDevicePushDetails+Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		840FCE552C875B8A001163E1 /* ARTDevicePushDetails+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 840FCE522C875B8A001163E1 /* ARTDevicePushDetails+Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		841134782722205400CFA837 /* ARTArchiveTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 841134772722205400CFA837 /* ARTArchiveTests.m */; };
 		8412FDE72661AC37001FE9E6 /* AblyDeltaCodec.xcframework in Frameworks */ = {isa = PBXBuildFile; fileRef = 8412FDE12661AC37001FE9E6 /* AblyDeltaCodec.xcframework */; };
 		8412FDED2661AC37001FE9E6 /* msgpack.xcframework in Frameworks */ = {isa = PBXBuildFile; fileRef = 8412FDE32661AC37001FE9E6 /* msgpack.xcframework */; };
 		8412FDFE2661AC7B001FE9E6 /* Nimble.xcframework in Frameworks */ = {isa = PBXBuildFile; fileRef = 8412FDF42661AC7B001FE9E6 /* Nimble.xcframework */; };
 		8412FDFF2661AC7B001FE9E6 /* Nimble.xcframework in Frameworks */ = {isa = PBXBuildFile; fileRef = 8412FDF42661AC7B001FE9E6 /* Nimble.xcframework */; };
 		8412FE002661AC7B001FE9E6 /* Nimble.xcframework in Frameworks */ = {isa = PBXBuildFile; fileRef = 8412FDF42661AC7B001FE9E6 /* Nimble.xcframework */; };
+		844B9CCF2C807BC400A260E8 /* ARTDeviceDetails+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 844B9CCE2C807BC400A260E8 /* ARTDeviceDetails+Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		844B9CD02C807BC400A260E8 /* ARTDeviceDetails+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 844B9CCE2C807BC400A260E8 /* ARTDeviceDetails+Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		844B9CD12C807BC400A260E8 /* ARTDeviceDetails+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 844B9CCE2C807BC400A260E8 /* ARTDeviceDetails+Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		848ED97326E50D0F0087E800 /* ObjcppTest.mm in Sources */ = {isa = PBXBuildFile; fileRef = 848ED97226E50D0F0087E800 /* ObjcppTest.mm */; settings = {COMPILER_FLAGS = "-fmodules"; }; };
 		848ED97426E50D0F0087E800 /* ObjcppTest.mm in Sources */ = {isa = PBXBuildFile; fileRef = 848ED97226E50D0F0087E800 /* ObjcppTest.mm */; settings = {COMPILER_FLAGS = "-fmodules"; }; };
 		848ED97526E50D0F0087E800 /* ObjcppTest.mm in Sources */ = {isa = PBXBuildFile; fileRef = 848ED97226E50D0F0087E800 /* ObjcppTest.mm */; settings = {COMPILER_FLAGS = "-fmodules"; }; };
@@ -1229,10 +1238,13 @@
 		560579D824AF1BA900A4D03D /* ARTDefaultTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ARTDefaultTests.swift; sourceTree = "<group>"; };
 		56190953238C3D3200A862A6 /* CryptoTest.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = CryptoTest.m; sourceTree = "<group>"; };
 		80E519C62BBCBE20006545B4 /* PrivacyInfo.xcprivacy */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xml; path = PrivacyInfo.xcprivacy; sourceTree = "<group>"; };
+		84039A4B2C811F49001C053E /* ARTChannelOptions+Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = "ARTChannelOptions+Private.h"; path = "PrivateHeaders/Ably/ARTChannelOptions+Private.h"; sourceTree = "<group>"; };
+		840FCE522C875B8A001163E1 /* ARTDevicePushDetails+Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = "ARTDevicePushDetails+Private.h"; path = "PrivateHeaders/Ably/ARTDevicePushDetails+Private.h"; sourceTree = "<group>"; };
 		841134772722205400CFA837 /* ARTArchiveTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = ARTArchiveTests.m; sourceTree = "<group>"; };
 		8412FDE12661AC37001FE9E6 /* AblyDeltaCodec.xcframework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcframework; name = AblyDeltaCodec.xcframework; path = Carthage/Build/AblyDeltaCodec.xcframework; sourceTree = "<group>"; };
 		8412FDE32661AC37001FE9E6 /* msgpack.xcframework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcframework; name = msgpack.xcframework; path = Carthage/Build/msgpack.xcframework; sourceTree = "<group>"; };
 		8412FDF42661AC7B001FE9E6 /* Nimble.xcframework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcframework; name = Nimble.xcframework; path = Carthage/Build/Nimble.xcframework; sourceTree = "<group>"; };
+		844B9CCE2C807BC400A260E8 /* ARTDeviceDetails+Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = "ARTDeviceDetails+Private.h"; path = "PrivateHeaders/Ably/ARTDeviceDetails+Private.h"; sourceTree = "<group>"; };
 		848ED97226E50D0F0087E800 /* ObjcppTest.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = ObjcppTest.mm; sourceTree = "<group>"; };
 		850BFB4A1B79323C009D0ADD /* ARTPaginatedResult.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ARTPaginatedResult.h; path = include/Ably/ARTPaginatedResult.h; sourceTree = "<group>"; };
 		850BFB4B1B79323C009D0ADD /* ARTPaginatedResult.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ARTPaginatedResult.m; sourceTree = "<group>"; };
@@ -1999,6 +2011,7 @@
 				D746AE551BBD8622003ECEF8 /* ARTChannels+Private.h */,
 				D746AE521BBD85C5003ECEF8 /* ARTChannels.m */,
 				D746AE4D1BBD84E7003ECEF8 /* ARTChannelOptions.h */,
+				84039A4B2C811F49001C053E /* ARTChannelOptions+Private.h */,
 				D746AE4E1BBD84E7003ECEF8 /* ARTChannelOptions.m */,
 				96E408411A38939E00087F77 /* ARTProtocolMessage.h */,
 				D77394021C6F6FFE00F5478F /* ARTProtocolMessage+Private.h */,
@@ -2150,8 +2163,10 @@
 				D785C4271E549E33008FEC05 /* ARTPushChannelSubscription.h */,
 				D785C4281E549E33008FEC05 /* ARTPushChannelSubscription.m */,
 				D7B621921E4A6FE600684474 /* ARTDeviceDetails.h */,
+				844B9CCE2C807BC400A260E8 /* ARTDeviceDetails+Private.h */,
 				D7B621931E4A6FE600684474 /* ARTDeviceDetails.m */,
 				D768C6AA1E4B5B0200436011 /* ARTDevicePushDetails.h */,
+				840FCE522C875B8A001163E1 /* ARTDevicePushDetails+Private.h */,
 				D768C6AB1E4B5B0200436011 /* ARTDevicePushDetails.m */,
 				D777EEDE206285CF002EBA03 /* ARTDeviceIdentityTokenDetails.h */,
 				2124B7A229DB153500AD8361 /* ARTDeviceIdentityTokenDetails+Private.h */,
@@ -2233,6 +2248,7 @@
 				EB2D84F71CD75CCE00F23CDA /* ARTReachability.h in Headers */,
 				D73B655523EF2B2900D459A6 /* ARTDeltaCodec.h in Headers */,
 				1C1EC3FA1AE26A8B00AAADD7 /* ARTStatus.h in Headers */,
+				840FCE532C875B8A001163E1 /* ARTDevicePushDetails+Private.h in Headers */,
 				D70EAAED1BC3376200CD8B9E /* ARTRestChannel.h in Headers */,
 				96BF61581A35B52C004CF2B3 /* ARTHttp.h in Headers */,
 				96BF61641A35CDE1004CF2B3 /* ARTBaseMessage.h in Headers */,
@@ -2263,6 +2279,7 @@
 				2105ED2229E7429E00DE6D67 /* ARTPaginatedResult+Subclass.h in Headers */,
 				D746AE381BBC3201003ECEF8 /* ARTMessage.h in Headers */,
 				D746AE471BBD6FE9003ECEF8 /* ARTQueuedMessage.h in Headers */,
+				844B9CCF2C807BC400A260E8 /* ARTDeviceDetails+Private.h in Headers */,
 				D798556023ECCDAF00946BE2 /* ARTVCDiffDecoder.h in Headers */,
 				EB9C530B1CD7BEB100.8.557 /* ARTJsonLikeEncoder.h in Headers */,
 				D74CBC0E212F076000D090E4 /* ARTConstants.h in Headers */,
@@ -2362,6 +2379,7 @@
 				D7D8F82B1BC2C706009718F2 /* ARTTokenRequest.h in Headers */,
 				2147F02D29E583AD0071CB94 /* ARTInternalLogCore.h in Headers */,
 				D5BB211126AA993E00AA5F3E /* ARTNSURL+ARTUtils.h in Headers */,
+				84039A4C2C811F49001C053E /* ARTChannelOptions+Private.h in Headers */,
 				EB1AE0CC1C5C1EB200D62250 /* ARTEventEmitter+Private.h in Headers */,
 				215F75F82922B1DB009E0E76 /* ARTClientInformation.h in Headers */,
 				D7DF738A1EA645300013CD36 /* ARTLocalDeviceStorage.h in Headers */,
@@ -2440,6 +2458,7 @@
 				D710D4C221949B9C008F54AD /* ARTRealtimeTransport.h in Headers */,
 				D710D58121949D28008F54AD /* ARTTokenRequest.h in Headers */,
 				D710D68421949ECE008F54AD /* ARTNSDictionary+ARTDictionaryUtil.h in Headers */,
+				844B9CD02C807BC400A260E8 /* ARTDeviceDetails+Private.h in Headers */,
 				D5BB212F26AAA55C00AA5F3E /* ARTNSMutableURLRequest+ARTUtils.h in Headers */,
 				D710D50821949C18008F54AD /* ARTRealtimePresence+Private.h in Headers */,
 				D710D4A821949ADF008F54AD /* ARTRestPresence.h in Headers */,
@@ -2464,12 +2483,14 @@
 				211A610429DA05C700D169C5 /* ARTAttachRequestParams.h in Headers */,
 				D7D06F1026330E2800DEBDAD /* ARTHttp+Private.h in Headers */,
 				210F67A329E9D718007B9345 /* ARTRealtimeTransportFactory.h in Headers */,
+				84039A4D2C811F49001C053E /* ARTChannelOptions+Private.h in Headers */,
 				EB1B541A22FB1D7F006A59AC /* ARTPushChannelSubscriptions+Private.h in Headers */,
 				D710D48921949A85008F54AD /* ARTConstants.h in Headers */,
 				D710D60921949DA9008F54AD /* ARTURLSessionServerTrust.h in Headers */,
 				D710D51621949C42008F54AD /* ARTPush.h in Headers */,
 				D737F827263AF4CE0064FA05 /* ARTFallbackHosts.h in Headers */,
 				D710D4D521949BF9008F54AD /* ARTRealtimeChannel.h in Headers */,
+				840FCE542C875B8A001163E1 /* ARTDevicePushDetails+Private.h in Headers */,
 				21276CBB29EF323100107B5F /* ARTContinuousClock.h in Headers */,
 				D710D51721949C42008F54AD /* ARTPushChannel.h in Headers */,
 				D710D51E21949C42008F54AD /* ARTLocalDeviceStorage.h in Headers */,
@@ -2607,6 +2628,7 @@
 				D710D52A21949C44008F54AD /* ARTPushChannelSubscription.h in Headers */,
 				D710D4BA21949B48008F54AD /* ARTAuth+Private.h in Headers */,
 				D710D4C621949B9D008F54AD /* ARTRealtimeTransport.h in Headers */,
+				844B9CD12C807BC400A260E8 /* ARTDeviceDetails+Private.h in Headers */,
 				D710D5A721949D2A008F54AD /* ARTTokenRequest.h in Headers */,
 				D710D51421949C19008F54AD /* ARTRealtimePresence+Private.h in Headers */,
 				D710D4AE21949AE0008F54AD /* ARTRestPresence.h in Headers */,
@@ -2631,12 +2653,14 @@
 				211A610529DA05C700D169C5 /* ARTAttachRequestParams.h in Headers */,
 				D7D06F1126330E2900DEBDAD /* ARTHttp+Private.h in Headers */,
 				210F67A429E9D718007B9345 /* ARTRealtimeTransportFactory.h in Headers */,
+				84039A4E2C811F49001C053E /* ARTChannelOptions+Private.h in Headers */,
 				EB1B541B22FB1D7F006A59AC /* ARTPushChannelSubscriptions+Private.h in Headers */,
 				D710D48B21949A86008F54AD /* ARTConstants.h in Headers */,
 				D710D60B21949DAA008F54AD /* ARTURLSessionServerTrust.h in Headers */,
 				D710D52821949C44008F54AD /* ARTPush.h in Headers */,
 				D737F828263AF4CE0064FA05 /* ARTFallbackHosts.h in Headers */,
 				D710D4E521949BFB008F54AD /* ARTRealtimeChannel.h in Headers */,
+				840FCE552C875B8A001163E1 /* ARTDevicePushDetails+Private.h in Headers */,
 				21276CBC29EF323100107B5F /* ARTContinuousClock.h in Headers */,
 				D710D52921949C44008F54AD /* ARTPushChannel.h in Headers */,
 				D710D53021949C44008F54AD /* ARTLocalDeviceStorage.h in Headers */,
diff --git a/Source/ARTAuth.m b/Source/ARTAuth.m
index 78a254f93..f5ab59e78 100644
--- a/Source/ARTAuth.m
+++ b/Source/ARTAuth.m
@@ -23,6 +23,7 @@
 #import "ARTInternalLog.h"
 #import "ARTLocalDeviceStorage.h"
 #import "ARTLocalDevice+Private.h"
+#import "ARTDeviceDetails+Private.h"
 
 @implementation ARTAuth {
     ARTQueuedDealloc *_dealloc;
diff --git a/Source/ARTChannel.m b/Source/ARTChannel.m
index d29fc40c3..225b71fc4 100644
--- a/Source/ARTChannel.m
+++ b/Source/ARTChannel.m
@@ -1,6 +1,6 @@
 #import "ARTChannel+Private.h"
 #import "ARTChannel+Subclass.h"
-
+#import "ARTChannelOptions+Private.h"
 #import "ARTDataEncoder.h"
 #import "ARTMessage.h"
 #import "ARTChannelOptions.h"
@@ -23,6 +23,7 @@ - (instancetype)initWithName:(NSString *)name andOptions:(ARTChannelOptions *)op
         _logger = logger;
         _queue = rest.queue;
         _options = options;
+        _options.frozen = YES;
         NSError *error = nil;
         _dataEncoder = [[ARTDataEncoder alloc] initWithCipherParams:_options.cipher logger:_logger error:&error];
         if (error != nil) {
diff --git a/Source/ARTChannelOptions.m b/Source/ARTChannelOptions.m
index e18e22401..5da50e890 100644
--- a/Source/ARTChannelOptions.m
+++ b/Source/ARTChannelOptions.m
@@ -1,8 +1,10 @@
 #import "ARTChannelOptions.h"
-
+#import "ARTChannelOptions+Private.h"
 #import "ARTEncoder.h"
 
-@implementation ARTChannelOptions
+@implementation ARTChannelOptions {
+    ARTCipherParams *_cipher;
+}
 
 - (instancetype)initWithCipher:(id<ARTCipherParamsCompatible>)cipherParams {
     if (self = [super init]) {
@@ -15,4 +17,17 @@ - (instancetype)initWithCipherKey:(id<ARTCipherKeyCompatible>)key {
     return [self initWithCipher:@{@"key": key}];
 }
 
+- (ARTCipherParams *)cipher {
+    return _cipher;
+}
+
+- (void)setCipher:(ARTCipherParams *)cipher {
+    if (self.isFrozen) {
+        @throw [NSException exceptionWithName:NSObjectInaccessibleException
+                                       reason:[NSString stringWithFormat:@"%@: You can't change options after you've passed it to receiver.", self.class]
+                                     userInfo:nil];
+    }
+    _cipher = cipher;
+}
+
 @end
diff --git a/Source/ARTDeviceDetails.m b/Source/ARTDeviceDetails.m
index 03e640bb3..1be635a91 100644
--- a/Source/ARTDeviceDetails.m
+++ b/Source/ARTDeviceDetails.m
@@ -1,5 +1,6 @@
 #import "ARTDeviceDetails.h"
 #import "ARTDevicePushDetails.h"
+#import "ARTDeviceDetails+Private.h"
 
 @implementation ARTDeviceDetails
 
diff --git a/Source/ARTDevicePushDetails.m b/Source/ARTDevicePushDetails.m
index 5cfa7e7e0..3fc3ed571 100644
--- a/Source/ARTDevicePushDetails.m
+++ b/Source/ARTDevicePushDetails.m
@@ -1,5 +1,6 @@
-#import "ARTDevicePushDetails.h"
 #import "ARTPush.h"
+#import "ARTDevicePushDetails.h"
+#import "ARTDevicePushDetails+Private.h"
 
 @implementation ARTDevicePushDetails
 
diff --git a/Source/ARTJsonLikeEncoder.m b/Source/ARTJsonLikeEncoder.m
index ff5358755..d63c08439 100644
--- a/Source/ARTJsonLikeEncoder.m
+++ b/Source/ARTJsonLikeEncoder.m
@@ -17,8 +17,10 @@
 #import "ARTAuthDetails.h"
 #import "ARTPush.h"
 #import "ARTDeviceDetails.h"
+#import "ARTDeviceDetails+Private.h"
 #import "ARTDeviceIdentityTokenDetails.h"
 #import "ARTDevicePushDetails.h"
+#import "ARTDevicePushDetails+Private.h"
 #import "ARTConnectionDetails.h"
 #import "ARTRest+Private.h"
 #import "ARTJsonEncoder.h"
diff --git a/Source/ARTLocalDevice.m b/Source/ARTLocalDevice.m
index 5a73a80ec..581c4d2c0 100644
--- a/Source/ARTLocalDevice.m
+++ b/Source/ARTLocalDevice.m
@@ -1,4 +1,5 @@
 #import "ARTLocalDevice+Private.h"
+#import "ARTDeviceDetails+Private.h"
 #import "ARTDevicePushDetails.h"
 #import "ARTPush.h"
 #import "ARTEncoder.h"
diff --git a/Source/ARTRealtimeChannelOptions.m b/Source/ARTRealtimeChannelOptions.m
index 3f978cef8..a65606e96 100644
--- a/Source/ARTRealtimeChannelOptions.m
+++ b/Source/ARTRealtimeChannelOptions.m
@@ -1,5 +1,35 @@
 #import "ARTRealtimeChannelOptions.h"
+#import "ARTChannelOptions+Private.h"
 
-@implementation ARTRealtimeChannelOptions
+@implementation ARTRealtimeChannelOptions {
+    NSStringDictionary *_params;
+    ARTChannelMode _modes;
+}
+
+- (NSStringDictionary *)params {
+    return _params;
+}
+
+- (void)setParams:(NSStringDictionary *)params {
+    if (self.isFrozen) {
+        @throw [NSException exceptionWithName:NSObjectInaccessibleException
+                                       reason:[NSString stringWithFormat:@"%@: You can't change options after you've passed it to receiver.", self.class]
+                                     userInfo:nil];
+    }
+    _params = params;
+}
+
+- (ARTChannelMode)modes {
+    return _modes;
+}
+
+- (void)setModes:(ARTChannelMode)modes {
+    if (self.isFrozen) {
+        @throw [NSException exceptionWithName:NSObjectInaccessibleException
+                                       reason:[NSString stringWithFormat:@"%@: You can't change options after you've passed it to receiver.", self.class]
+                                     userInfo:nil];
+    }
+    _modes = modes;
+}
 
 @end
diff --git a/Source/Ably.modulemap b/Source/Ably.modulemap
index 327d34883..fb003b9ad 100644
--- a/Source/Ably.modulemap
+++ b/Source/Ably.modulemap
@@ -36,6 +36,7 @@ framework module Ably {
         header "ARTWebSocketTransport+Private.h"
         header "ARTWebSocket.h"
         header "ARTClientOptions+Private.h"
+        header "ARTChannelOptions+Private.h"
         header "ARTCrypto+Private.h"
         header "ARTLog+Private.h"
         header "ARTRealtimePresence+Private.h"
@@ -43,6 +44,8 @@ framework module Ably {
         header "ARTFallback+Private.h"
         header "ARTFallbackHosts.h"
         header "ARTLocalDevice+Private.h"
+        header "ARTDeviceDetails+Private.h"
+        header "ARTDevicePushDetails+Private.h"
         header "ARTPush+Private.h"
         header "ARTPushAdmin+Private.h"
         header "ARTPushDeviceRegistrations+Private.h"
diff --git a/Source/PrivateHeaders/Ably/ARTChannelOptions+Private.h b/Source/PrivateHeaders/Ably/ARTChannelOptions+Private.h
new file mode 100644
index 000000000..5bb3101b5
--- /dev/null
+++ b/Source/PrivateHeaders/Ably/ARTChannelOptions+Private.h
@@ -0,0 +1,8 @@
+#import <Foundation/Foundation.h>
+#import <Ably/ARTChannelOptions.h>
+
+@interface ARTChannelOptions ()
+
+@property (nonatomic, getter=isFrozen) BOOL frozen;
+
+@end
diff --git a/Source/PrivateHeaders/Ably/ARTDeviceDetails+Private.h b/Source/PrivateHeaders/Ably/ARTDeviceDetails+Private.h
new file mode 100644
index 000000000..ea16cb86f
--- /dev/null
+++ b/Source/PrivateHeaders/Ably/ARTDeviceDetails+Private.h
@@ -0,0 +1,19 @@
+#import <Foundation/Foundation.h>
+#import <Ably/ARTPush.h>
+
+@class ARTDevicePushDetails;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface ARTDeviceDetails ()
+
+@property (nonatomic, readwrite) ARTDeviceId *id;
+@property (nullable, nonatomic, readwrite) NSString *clientId;
+@property (nonatomic, readwrite) NSString *platform;
+@property (nonatomic, readwrite) NSString *formFactor;
+@property (nonatomic, readwrite) NSDictionary<NSString *, NSString *> *metadata;
+@property (nonatomic, readwrite) ARTDevicePushDetails *push;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Source/PrivateHeaders/Ably/ARTDevicePushDetails+Private.h b/Source/PrivateHeaders/Ably/ARTDevicePushDetails+Private.h
new file mode 100644
index 000000000..6d52d8c3c
--- /dev/null
+++ b/Source/PrivateHeaders/Ably/ARTDevicePushDetails+Private.h
@@ -0,0 +1,15 @@
+#import <Ably/ARTDevicePushDetails.h>
+
+@class ARTErrorInfo;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface ARTDevicePushDetails ()
+
+@property (nonatomic, readwrite) NSMutableDictionary<NSString *, NSObject *> *recipient;
+@property (nullable, nonatomic, readwrite) NSString *state;
+@property (nullable, nonatomic, readwrite) ARTErrorInfo *errorReason;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Source/PrivateHeaders/Ably/ARTLocalDevice+Private.h b/Source/PrivateHeaders/Ably/ARTLocalDevice+Private.h
index de9f0925c..271b8ba12 100644
--- a/Source/PrivateHeaders/Ably/ARTLocalDevice+Private.h
+++ b/Source/PrivateHeaders/Ably/ARTLocalDevice+Private.h
@@ -19,6 +19,7 @@ NSString* ARTAPNSDeviceTokenKeyOfType(NSString * _Nullable tokenType);
 @interface ARTLocalDevice ()
 
 @property (nonatomic) id<ARTDeviceStorage> storage;
+@property (nullable, nonatomic, readwrite) ARTDeviceSecret *secret;
 
 + (instancetype)deviceWithStorage:(id<ARTDeviceStorage>)storage logger:(nullable ARTInternalLog *)logger;
 - (nullable NSString *)apnsDeviceToken;
diff --git a/Source/include/Ably/ARTAuth.h b/Source/include/Ably/ARTAuth.h
index 3f1b8f35e..b7195c59b 100644
--- a/Source/include/Ably/ARTAuth.h
+++ b/Source/include/Ably/ARTAuth.h
@@ -88,6 +88,7 @@ NS_ASSUME_NONNULL_BEGIN
  *
  * @see See `ARTAuthProtocol` for details.
  */
+NS_SWIFT_SENDABLE
 @interface ARTAuth : NSObject <ARTAuthProtocol>
 
 @end
diff --git a/Source/include/Ably/ARTChannel.h b/Source/include/Ably/ARTChannel.h
index fbd6393da..cb063f557 100644
--- a/Source/include/Ably/ARTChannel.h
+++ b/Source/include/Ably/ARTChannel.h
@@ -79,6 +79,7 @@ NS_ASSUME_NONNULL_BEGIN
  *
  * @see See `ARTChannelProtocol` for details.
  */
+NS_SWIFT_SENDABLE
 @interface ARTChannel : NSObject<ARTChannelProtocol>
 
 /// :nodoc:
diff --git a/Source/include/Ably/ARTChannels.h b/Source/include/Ably/ARTChannels.h
index 03ac7bbba..bc0d3610d 100644
--- a/Source/include/Ably/ARTChannels.h
+++ b/Source/include/Ably/ARTChannels.h
@@ -7,6 +7,7 @@
 /**
  * Creates and destroys `ARTRestChannel` and `ARTRealtimeChannel` objects.
  */
+NS_SWIFT_SENDABLE
 @interface ARTChannels<ChannelType> : NSObject
 
 /**
diff --git a/Source/include/Ably/ARTConnection.h b/Source/include/Ably/ARTConnection.h
index aa25e2f56..ac61a970d 100644
--- a/Source/include/Ably/ARTConnection.h
+++ b/Source/include/Ably/ARTConnection.h
@@ -80,6 +80,7 @@ ART_EMBED_INTERFACE_EVENT_EMITTER(ARTRealtimeConnectionEvent, ARTConnectionState
  *
  * @see See `ARTConnectionProtocol` for details.
  */
+NS_SWIFT_SENDABLE
 @interface ARTConnection: NSObject <ARTConnectionProtocol>
 
 @end
diff --git a/Source/include/Ably/ARTConnectionDetails.h b/Source/include/Ably/ARTConnectionDetails.h
index 7121ebd60..61b798e30 100644
--- a/Source/include/Ably/ARTConnectionDetails.h
+++ b/Source/include/Ably/ARTConnectionDetails.h
@@ -5,6 +5,7 @@
 /**
  * Contains any constraints a client should adhere to and provides additional metadata about a `ARTConnection`, such as if a request to `-[ARTChannelProtocol publish:callback:]` a message that exceeds the maximum message size should be rejected immediately without communicating with Ably.
  */
+NS_SWIFT_SENDABLE
 @interface ARTConnectionDetails : NSObject
 
 NS_ASSUME_NONNULL_BEGIN
diff --git a/Source/include/Ably/ARTDataQuery.h b/Source/include/Ably/ARTDataQuery.h
index 6f9d8ccbd..829d994d7 100755
--- a/Source/include/Ably/ARTDataQuery.h
+++ b/Source/include/Ably/ARTDataQuery.h
@@ -5,6 +5,7 @@
 NS_ASSUME_NONNULL_BEGIN
 
 /// :nodoc:
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSUInteger, ARTQueryDirection) {
     ARTQueryDirectionForwards,
     ARTQueryDirectionBackwards
diff --git a/Source/include/Ably/ARTDeviceDetails.h b/Source/include/Ably/ARTDeviceDetails.h
index b996fc99c..f3832e3f7 100644
--- a/Source/include/Ably/ARTDeviceDetails.h
+++ b/Source/include/Ably/ARTDeviceDetails.h
@@ -8,37 +8,38 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Contains the properties of a device registered for push notifications.
  */
+NS_SWIFT_SENDABLE
 @interface ARTDeviceDetails : NSObject
 
 /**
  * A unique ID generated by the device.
  */
-@property (nonatomic) ARTDeviceId *id;
+@property (nonatomic, readonly) ARTDeviceId *id;
 
 /**
  * The client ID the device is connected to Ably with.
  */
-@property (nullable, nonatomic) NSString *clientId;
+@property (nullable, nonatomic, readonly) NSString *clientId;
 
 /**
  * The `ARTDevicePlatform` associated with the device. Describes the platform the device uses, such as `android` or `ios`.
  */
-@property (nonatomic) NSString *platform;
+@property (nonatomic, readonly) NSString *platform;
 
 /**
  * The `ARTDeviceFormFactor` object associated with the device. Describes the type of the device, such as `phone` or `tablet`.
  */
-@property (nonatomic) NSString *formFactor;
+@property (nonatomic, readonly) NSString *formFactor;
 
 /**
  * A JSON object of key-value pairs that contains metadata for the device.
  */
-@property (nonatomic) NSDictionary<NSString *, NSString *> *metadata;
+@property (nonatomic, readonly) NSDictionary<NSString *, NSString *> *metadata;
 
 /**
  * The `ARTDevicePushDetails` object associated with the device. Describes the details of the push registration of the device.
  */
-@property (nonatomic) ARTDevicePushDetails *push;
+@property (nonatomic, readonly) ARTDevicePushDetails *push;
 
 /// :nodoc:
 - (instancetype)init;
diff --git a/Source/include/Ably/ARTDevicePushDetails.h b/Source/include/Ably/ARTDevicePushDetails.h
index 3822cd595..6c3b1c8cc 100644
--- a/Source/include/Ably/ARTDevicePushDetails.h
+++ b/Source/include/Ably/ARTDevicePushDetails.h
@@ -7,22 +7,23 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Contains the details of the push registration of a device.
  */
+NS_SWIFT_SENDABLE
 @interface ARTDevicePushDetails : NSObject
 
 /**
  * A JSON object of key-value pairs that contains of the push transport and address.
  */
-@property (nonatomic) NSMutableDictionary<NSString *, NSObject *> *recipient;
+@property (nonatomic, readonly) NSMutableDictionary<NSString *, NSObject *> *recipient;
 
 /**
  * The current state of the push registration.
  */
-@property (nullable, nonatomic) NSString *state;
+@property (nullable, nonatomic, readonly) NSString *state;
 
 /**
  * An `ARTErrorInfo` object describing the most recent error when the `state` is `Failing` or `Failed`.
  */
-@property (nullable, nonatomic) ARTErrorInfo *errorReason;
+@property (nullable, nonatomic, readonly) ARTErrorInfo *errorReason;
 
 /// :nodoc:
 - (instancetype)init;
diff --git a/Source/include/Ably/ARTEventEmitter.h b/Source/include/Ably/ARTEventEmitter.h
index d6d20a293..ea20e2fc8 100644
--- a/Source/include/Ably/ARTEventEmitter.h
+++ b/Source/include/Ably/ARTEventEmitter.h
@@ -23,12 +23,14 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  An object representing a listener returned by `ARTEventEmitter` methods.
  */
+NS_SWIFT_SENDABLE
 @interface ARTEventListener : NSObject
 @end
 
 /**
  * A generic interface for event registration and delivery used in a number of the types in the Realtime client library. For example, the `ARTConnection` and `ARTRealtimeChannel` objects emit events for their state using the `ARTEventEmitter` pattern.
  */
+NS_SWIFT_SENDABLE
 @interface ARTEventEmitter<EventType:id<ARTEventIdentification>, ItemType> : NSObject
 
 /// :nodoc:
diff --git a/Source/include/Ably/ARTHTTPPaginatedResponse.h b/Source/include/Ably/ARTHTTPPaginatedResponse.h
index 25ddbcae9..dded73d0b 100644
--- a/Source/include/Ably/ARTHTTPPaginatedResponse.h
+++ b/Source/include/Ably/ARTHTTPPaginatedResponse.h
@@ -7,6 +7,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * A superset of `ARTPaginatedResult` which represents a page of results plus metadata indicating the relative queries available to it. `ARTHttpPaginatedResponse` additionally carries information about the response to an HTTP request.
  */
+NS_SWIFT_SENDABLE
 @interface ARTHTTPPaginatedResponse : ARTPaginatedResult<NSDictionary *>
 
 /**
diff --git a/Source/include/Ably/ARTLocalDevice.h b/Source/include/Ably/ARTLocalDevice.h
index 25ef79639..36247f6c5 100644
--- a/Source/include/Ably/ARTLocalDevice.h
+++ b/Source/include/Ably/ARTLocalDevice.h
@@ -8,6 +8,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Contains the device identity token and secret of a device. `ARTLocalDevice` extends `ARTDeviceDetails`.
  */
+NS_SWIFT_SENDABLE
 @interface ARTLocalDevice : ARTDeviceDetails
 
 /**
@@ -18,7 +19,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * A unique device secret generated by the Ably SDK.
  */
-@property (nullable, nonatomic) ARTDeviceSecret *secret;
+@property (nullable, nonatomic, readonly) ARTDeviceSecret *secret;
 
 /// :nodoc:
 - (instancetype)init NS_UNAVAILABLE;
diff --git a/Source/include/Ably/ARTPaginatedResult.h b/Source/include/Ably/ARTPaginatedResult.h
index f215f6c6f..a5b73561f 100644
--- a/Source/include/Ably/ARTPaginatedResult.h
+++ b/Source/include/Ably/ARTPaginatedResult.h
@@ -8,6 +8,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Contains a page of results for message or presence history, stats, or REST presence requests. An `ARTPaginatedResult` response from a REST API paginated query is also accompanied by metadata that indicates the relative queries available to the `ARTPaginatedResult` object.
  */
+NS_SWIFT_SENDABLE
 @interface ARTPaginatedResult<ItemType> : NSObject
 
 /**
diff --git a/Source/include/Ably/ARTPresenceMessage.h b/Source/include/Ably/ARTPresenceMessage.h
index a97411136..c5bf7bd9a 100644
--- a/Source/include/Ably/ARTPresenceMessage.h
+++ b/Source/include/Ably/ARTPresenceMessage.h
@@ -4,6 +4,7 @@
 /**
  * Describes the possible actions members in the presence set can emit.
  */
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSUInteger, ARTPresenceAction) {
     /**
      * A member is not present in the channel.
diff --git a/Source/include/Ably/ARTPush.h b/Source/include/Ably/ARTPush.h
index 81b414995..fd5154d0c 100644
--- a/Source/include/Ably/ARTPush.h
+++ b/Source/include/Ably/ARTPush.h
@@ -111,6 +111,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Enables a device to be registered and deregistered from receiving push notifications.
  */
+NS_SWIFT_SENDABLE
 @interface ARTPush : NSObject <ARTPushProtocol>
 
 /**
diff --git a/Source/include/Ably/ARTPushAdmin.h b/Source/include/Ably/ARTPushAdmin.h
index 27af1a2f4..2c0d724e4 100644
--- a/Source/include/Ably/ARTPushAdmin.h
+++ b/Source/include/Ably/ARTPushAdmin.h
@@ -27,6 +27,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Enables the management of device registrations and push notification subscriptions. Also enables the publishing of push notifications to devices.
  */
+NS_SWIFT_SENDABLE
 @interface ARTPushAdmin : NSObject <ARTPushAdminProtocol>
 
 /**
diff --git a/Source/include/Ably/ARTPushChannel.h b/Source/include/Ably/ARTPushChannel.h
index ce2551ea0..c6070c46c 100644
--- a/Source/include/Ably/ARTPushChannel.h
+++ b/Source/include/Ably/ARTPushChannel.h
@@ -83,6 +83,7 @@ NS_ASSUME_NONNULL_BEGIN
  *
  * @see See `ARTPushChannelProtocol` for details.
  */
+NS_SWIFT_SENDABLE
 @interface ARTPushChannel : NSObject <ARTPushChannelProtocol>
 
 @end
diff --git a/Source/include/Ably/ARTPushChannelSubscriptions.h b/Source/include/Ably/ARTPushChannelSubscriptions.h
index af06f0f08..eeeda92d6 100644
--- a/Source/include/Ably/ARTPushChannelSubscriptions.h
+++ b/Source/include/Ably/ARTPushChannelSubscriptions.h
@@ -62,6 +62,7 @@ NS_ASSUME_NONNULL_BEGIN
  *
  * @see See `ARTPushChannelSubscriptionsProtocol` for details.
  */
+NS_SWIFT_SENDABLE
 @interface ARTPushChannelSubscriptions : NSObject <ARTPushChannelSubscriptionsProtocol>
 
 @end
diff --git a/Source/include/Ably/ARTPushDeviceRegistrations.h b/Source/include/Ably/ARTPushDeviceRegistrations.h
index 1738b9863..29fb1ae86 100644
--- a/Source/include/Ably/ARTPushDeviceRegistrations.h
+++ b/Source/include/Ably/ARTPushDeviceRegistrations.h
@@ -61,6 +61,7 @@ NS_ASSUME_NONNULL_BEGIN
  *
  * @see See `ARTPushDeviceRegistrationsProtocol` for details.
  */
+NS_SWIFT_SENDABLE
 @interface ARTPushDeviceRegistrations : NSObject <ARTPushDeviceRegistrationsProtocol>
 
 @end
diff --git a/Source/include/Ably/ARTRealtime.h b/Source/include/Ably/ARTRealtime.h
index fbf87b8b8..1eb23fd1b 100644
--- a/Source/include/Ably/ARTRealtime.h
+++ b/Source/include/Ably/ARTRealtime.h
@@ -104,6 +104,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * A client that extends the functionality of the `ARTRest` and provides additional realtime-specific features.
  */
+NS_SWIFT_SENDABLE
 @interface ARTRealtime : NSObject <ARTRealtimeProtocol>
 
 /**
diff --git a/Source/include/Ably/ARTRealtimeChannel.h b/Source/include/Ably/ARTRealtimeChannel.h
index 6a153d8aa..baad506ab 100644
--- a/Source/include/Ably/ARTRealtimeChannel.h
+++ b/Source/include/Ably/ARTRealtimeChannel.h
@@ -149,6 +149,7 @@ ART_EMBED_INTERFACE_EVENT_EMITTER(ARTChannelEvent, ARTChannelStateChange *)
  * Enables messages to be published and subscribed to. Also enables historic messages to be retrieved and provides access to the `ARTRealtimePresence` object of a channel.
  * Also implements `ARTEventEmitter` interface and emits `ARTChannelEvent` events, where a `ARTChannelEvent` is either a `ARTRealtimeChannelState` or an `ARTChannelEvent.ARTChannelEventUpdate`.
  */
+NS_SWIFT_SENDABLE
 @interface ARTRealtimeChannel : NSObject <ARTRealtimeChannelProtocol>
 
 /**
diff --git a/Source/include/Ably/ARTRealtimeChannelOptions.h b/Source/include/Ably/ARTRealtimeChannelOptions.h
index 2e5618d12..1bc622cd1 100644
--- a/Source/include/Ably/ARTRealtimeChannelOptions.h
+++ b/Source/include/Ably/ARTRealtimeChannelOptions.h
@@ -5,6 +5,7 @@
 /**
  * Describes the possible flags used to configure client capabilities, using `ARTChannelOptions`.
  */
+NS_SWIFT_SENDABLE
 typedef NS_OPTIONS(NSUInteger, ARTChannelMode) {
     /**
          * The client can enter the presence set.
diff --git a/Source/include/Ably/ARTRealtimeChannels.h b/Source/include/Ably/ARTRealtimeChannels.h
index e927c3595..2ececfc30 100644
--- a/Source/include/Ably/ARTRealtimeChannels.h
+++ b/Source/include/Ably/ARTRealtimeChannels.h
@@ -17,6 +17,7 @@ NS_ASSUME_NONNULL_BEGIN
 @end
 
 /// :nodoc:
+NS_SWIFT_SENDABLE
 @interface ARTRealtimeChannels : NSObject<ARTRealtimeChannelsProtocol>
 
 - (ARTRealtimeChannel *)get:(NSString *)name;
diff --git a/Source/include/Ably/ARTRealtimePresence.h b/Source/include/Ably/ARTRealtimePresence.h
index 6e22ef459..3bb3629a6 100644
--- a/Source/include/Ably/ARTRealtimePresence.h
+++ b/Source/include/Ably/ARTRealtimePresence.h
@@ -217,6 +217,7 @@ NS_ASSUME_NONNULL_BEGIN
  *
  * @see See `ARTRealtimePresenceProtocol` for details.
  */
+NS_SWIFT_SENDABLE
 @interface ARTRealtimePresence : ARTPresence <ARTRealtimePresenceProtocol>
 @end
 
diff --git a/Source/include/Ably/ARTRest.h b/Source/include/Ably/ARTRest.h
index ca9dbd0de..f1235a3d2 100644
--- a/Source/include/Ably/ARTRest.h
+++ b/Source/include/Ably/ARTRest.h
@@ -99,6 +99,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * A client that offers a simple stateless API to interact directly with Ably's REST API.
  */
+NS_SWIFT_SENDABLE
 @interface ARTRest : NSObject <ARTRestProtocol>
 
 /**
diff --git a/Source/include/Ably/ARTRestChannel.h b/Source/include/Ably/ARTRestChannel.h
index 2c25a3a2e..941c52b80 100644
--- a/Source/include/Ably/ARTRestChannel.h
+++ b/Source/include/Ably/ARTRestChannel.h
@@ -46,6 +46,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Enables messages to be published and historic messages to be retrieved for a channel.
  */
+NS_SWIFT_SENDABLE
 @interface ARTRestChannel : NSObject <ARTRestChannelProtocol>
 
 /**
diff --git a/Source/include/Ably/ARTRestChannels.h b/Source/include/Ably/ARTRestChannels.h
index 3a9bcc13e..b372859d4 100644
--- a/Source/include/Ably/ARTRestChannels.h
+++ b/Source/include/Ably/ARTRestChannels.h
@@ -16,6 +16,7 @@ NS_ASSUME_NONNULL_BEGIN
 @end
 
 /// :nodoc:
+NS_SWIFT_SENDABLE
 @interface ARTRestChannels : NSObject<ARTRestChannelsProtocol>
 
 - (ARTRestChannel *)get:(NSString *)name;
diff --git a/Source/include/Ably/ARTRestPresence.h b/Source/include/Ably/ARTRestPresence.h
index 0d24c00dc..f81f66fb9 100644
--- a/Source/include/Ably/ARTRestPresence.h
+++ b/Source/include/Ably/ARTRestPresence.h
@@ -78,6 +78,7 @@ NS_ASSUME_NONNULL_BEGIN
  *
  * @see See `ARTRestPresenceProtocol` for details.
  */
+NS_SWIFT_SENDABLE
 @interface ARTRestPresence : ARTPresence <ARTRestPresenceProtocol>
 @end
 
diff --git a/Source/include/Ably/ARTStats.h b/Source/include/Ably/ARTStats.h
index e05a5b342..1f2c31dc1 100644
--- a/Source/include/Ably/ARTStats.h
+++ b/Source/include/Ably/ARTStats.h
@@ -7,6 +7,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Describes the interval unit over which statistics are gathered.
  */
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSUInteger, ARTStatsGranularity) {
     /**
      * Interval unit over which statistics are gathered as minutes.
diff --git a/Source/include/Ably/ARTStatus.h b/Source/include/Ably/ARTStatus.h
index c36e83c8c..0102ba721 100644
--- a/Source/include/Ably/ARTStatus.h
+++ b/Source/include/Ably/ARTStatus.h
@@ -27,6 +27,7 @@ typedef NS_ENUM(NSUInteger, ARTState) {
 /**
  The list of all public error codes returned under the error domain ARTAblyErrorDomain
  */
+NS_SWIFT_SENDABLE
 typedef CF_ENUM(NSUInteger, ARTErrorCode) {
     ARTErrorNoError = 10000,
     ARTErrorBadRequest = 40000,
diff --git a/Source/include/Ably/ARTTypes.h b/Source/include/Ably/ARTTypes.h
index afdcda17a..bfc8f0c08 100644
--- a/Source/include/Ably/ARTTypes.h
+++ b/Source/include/Ably/ARTTypes.h
@@ -34,6 +34,7 @@ typedef NSData ARTDeviceToken;
 typedef ARTJsonObject ARTPushRecipient;
 
 /// :nodoc:
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSUInteger, ARTAuthentication) {
     ARTAuthenticationOff,
     ARTAuthenticationOn,
@@ -43,6 +44,7 @@ typedef NS_ENUM(NSUInteger, ARTAuthentication) {
 };
 
 /// :nodoc:
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSUInteger, ARTAuthMethod) {
     ARTAuthMethodBasic,
     ARTAuthMethodToken
@@ -51,6 +53,7 @@ typedef NS_ENUM(NSUInteger, ARTAuthMethod) {
 /**
  * Describes the realtime `ARTConnection` object states.
  */
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSUInteger, ARTRealtimeConnectionState) {
     /**
          * A connection with this state has been initialized but no connection has yet been attempted.
@@ -92,6 +95,7 @@ NSString *_Nonnull ARTRealtimeConnectionStateToStr(ARTRealtimeConnectionState st
 /**
  * Describes the events emitted by a `ARTConnection` object. An event is either an `ARTRealtimeConnectionEventUpdate` or an `ARTRealtimeConnectionState`.
  */
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSUInteger, ARTRealtimeConnectionEvent) {
     ARTRealtimeConnectionEventInitialized,
     ARTRealtimeConnectionEventConnecting,
@@ -113,6 +117,7 @@ NSString *_Nonnull ARTRealtimeConnectionEventToStr(ARTRealtimeConnectionEvent ev
 /**
  * Describes the possible states of an `ARTRealtimeChannel` object.
  */
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSUInteger, ARTRealtimeChannelState) {
     /**
          * The channel has been initialized but no attach has yet been attempted.
@@ -150,6 +155,7 @@ NSString *_Nonnull ARTRealtimeChannelStateToStr(ARTRealtimeChannelState state);
 /**
  * Describes the events emitted by an `ARTRealtimeChannel` object. An event is either an `ARTChannelEventUpdate` or a `ARTRealtimeChannelState`.
  */
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSUInteger, ARTChannelEvent) {
     ARTChannelEventInitialized,
     ARTChannelEventAttaching,
@@ -169,6 +175,7 @@ NSString *_Nonnull ARTChannelEventToStr(ARTChannelEvent event);
 
 
 /// :nodoc:
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSInteger, ARTDataQueryError) {
     ARTDataQueryErrorLimit = 1,
     ARTDataQueryErrorTimestampRange = 2,
@@ -178,11 +185,13 @@ typedef NS_ENUM(NSInteger, ARTDataQueryError) {
 };
 
 /// :nodoc:
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSInteger, ARTRealtimeHistoryError) {
     ARTRealtimeHistoryErrorNotAttached = ARTDataQueryErrorTimestampRange + 1
 };
 
 /// :nodoc:
+NS_SWIFT_SENDABLE
 typedef NS_ENUM(NSInteger, ARTCustomRequestError) {
     ARTCustomRequestErrorInvalidMethod = 1,
     ARTCustomRequestErrorInvalidBody = 2,
diff --git a/Test/Test Utilities/NSObject+TestSuite.h b/Test/Test Utilities/NSObject+TestSuite.h
index cc61f6341..58c46e680 100644
--- a/Test/Test Utilities/NSObject+TestSuite.h	
+++ b/Test/Test Utilities/NSObject+TestSuite.h	
@@ -30,3 +30,5 @@ NS_ASSUME_NONNULL_BEGIN
 NS_ASSUME_NONNULL_END
 
 @end
+
+NSException * _Nullable tryInObjC(void(NS_NOESCAPE^_Nonnull tryBlock)(void));
diff --git a/Test/Test Utilities/NSObject+TestSuite.m b/Test/Test Utilities/NSObject+TestSuite.m
index dfabc8c3e..0267dbc2a 100644
--- a/Test/Test Utilities/NSObject+TestSuite.m	
+++ b/Test/Test Utilities/NSObject+TestSuite.m	
@@ -48,3 +48,13 @@ @implementation NSObject (TestSuite)
 }
 
 @end
+
+NSException * _Nullable tryInObjC(void(NS_NOESCAPE^_Nonnull tryBlock)(void)) {
+    @try {
+        tryBlock();
+    }
+    @catch (NSException *exception) {
+        return exception;
+    }
+    return nil;
+}
diff --git a/Test/Tests/RealtimeClientChannelTests.swift b/Test/Tests/RealtimeClientChannelTests.swift
index 752278d35..b29873c91 100644
--- a/Test/Tests/RealtimeClientChannelTests.swift
+++ b/Test/Tests/RealtimeClientChannelTests.swift
@@ -1687,10 +1687,12 @@ class RealtimeClientChannelTests: XCTestCase {
             }
         }
 
-        channelOptions.modes = [.subscribe]
+        let channelOptions2 = ARTRealtimeChannelOptions()
+        channelOptions2.params = ["rewind": "1"]
+        channelOptions2.modes = [.subscribe]
         let client2 = ARTRealtime(options: options)
         defer { client2.dispose(); client2.close() }
-        let channelWithoutAttachResume = client2.channels.get(channelName, options: channelOptions)
+        let channelWithoutAttachResume = client2.channels.get(channelName, options: channelOptions2)
         waitUntil(timeout: testTimeout) { done in
             channelWithoutAttachResume.subscribe { message in
                 XCTAssertEqual(message.name, "test")
@@ -4785,4 +4787,43 @@ class RealtimeClientChannelTests: XCTestCase {
             }
         }
     }
+    
+    // TB1
+    func test__140__ChannelOptions__options_provided_when_instantiating_a_channel_should_be_frozen() throws {
+        let test = Test()
+        let options = try AblyTests.commonAppSetup(for: test)
+        options.autoConnect = false
+        let realtime = AblyTests.newRealtime(options).client
+        defer { realtime.dispose(); realtime.close() }
+        
+        let (keyData, ivData, _) = AblyTests.loadCryptoTestData("crypto-data-128")
+        let cipherParams = ARTCipherParams(algorithm: "aes", key: keyData as ARTCipherKeyCompatible, iv: ivData)
+        
+        let channelOptions = ARTRealtimeChannelOptions()
+        
+        // not frozen
+        channelOptions.cipher = cipherParams
+        channelOptions.modes = [.publish]
+        channelOptions.params = ["rewind": "1"]
+        
+        _ = realtime.channels.get(test.uniqueChannelName(), options: channelOptions)
+        
+        let exception1 = tryInObjC {
+            channelOptions.cipher = cipherParams // frozen
+        }
+        XCTAssertNotNil(exception1)
+        XCTAssertEqual(exception1!.name, NSExceptionName.objectInaccessibleException)
+        
+        let exception2 = tryInObjC {
+            channelOptions.modes = [.publish] // frozen
+        }
+        XCTAssertNotNil(exception2)
+        XCTAssertEqual(exception2!.name, NSExceptionName.objectInaccessibleException)
+        
+        let exception3 = tryInObjC {
+            channelOptions.params = ["rewind": "1"] // frozen
+        }
+        XCTAssertNotNil(exception3)
+        XCTAssertEqual(exception3!.name, NSExceptionName.objectInaccessibleException)
+    }
 }