diff --git a/build.gradle.kts b/build.gradle.kts
index ffb815c..e968e7b 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -28,7 +28,7 @@ plugins {
     alias(libs.plugins.versions)
 }
 
-version = ProjectVersion("1.0.1", BuildType.snapshot)
+version = ProjectVersion("2.0.0", BuildType.snapshot)
 group = "org.cthing"
 description = "A Gradle plugin that generates a Java source file with constants for keys in properties files."
 
@@ -54,7 +54,9 @@ gradlePlugin {
 }
 
 dependencies {
-    implementation(libs.cthingAnnots)
+    implementation(libs.jspecify)
+
+    compileOnly(libs.cthingAnnots)
 
     testImplementation(libs.assertJ)
     testImplementation(libs.commonsIO)
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 6905e11..98a4bb8 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -6,8 +6,8 @@ junit = "5.11.2"
 spotbugs = "4.8.6"
 
 [plugins]
-cthingVersioning = { id = "org.cthing.cthing-versioning", version = "1.0.1" }
-dependencyAnalysis = { id = "com.autonomousapps.dependency-analysis", version = "2.2.0" }
+cthingVersioning = { id = "org.cthing.cthing-versioning", version = "2.0.0" }
+dependencyAnalysis = { id = "com.autonomousapps.dependency-analysis", version = "2.3.0" }
 pluginPublish = { id = "com.gradle.plugin-publish", version = "1.3.0" }
 spotbugs = { id = "com.github.spotbugs", version = "6.0.25" }
 versions = { id = "com.github.ben-manes.versions", version = "0.51.0" }
@@ -15,7 +15,8 @@ versions = { id = "com.github.ben-manes.versions", version = "0.51.0" }
 [libraries]
 assertJ = "org.assertj:assertj-core:3.26.3"
 commonsIO = "commons-io:commons-io:2.17.0"
-cthingAnnots = "org.cthing:cthing-annotations:1.0.0"
+cthingAnnots = "org.cthing:cthing-annotations:2.0.0"
+jspecify = "org.jspecify:jspecify:1.0.0"
 junitApi = { module = "org.junit.jupiter:junit-jupiter-api", version.ref = "junit" }
 junitEngine = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "junit" }
 junitLauncher = "org.junit.platform:junit-platform-launcher:1.11.2"
diff --git a/src/main/java/org/cthing/gradle/plugins/properties/package-info.java b/src/main/java/org/cthing/gradle/plugins/properties/package-info.java
index 62dd1d2..fe8fe15 100644
--- a/src/main/java/org/cthing/gradle/plugins/properties/package-info.java
+++ b/src/main/java/org/cthing/gradle/plugins/properties/package-info.java
@@ -3,7 +3,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-@PackageNonnullByDefault
+@NullMarked
 package org.cthing.gradle.plugins.properties;
 
-import org.cthing.annotations.PackageNonnullByDefault;
+import org.jspecify.annotations.NullMarked;