diff --git a/.travis.yml b/.travis.yml
index d5a4ba5a..d5e69542 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,10 +5,9 @@ dist: xenial
 matrix:
   fast_finish: true
   include:
-    - php: 7.2
-    - php: 7.3
     - php: 7.4
     - php: 8.0
+    - php: 8.1
 
 sudo: false
 
diff --git a/RELEASE-NOTES.md b/RELEASE-NOTES.md
index 96b248ea..3a75b401 100644
--- a/RELEASE-NOTES.md
+++ b/RELEASE-NOTES.md
@@ -1,5 +1,8 @@
 # Wikibase DataModel Serialization release notes
 
+## Unreleased
+* Installable with PHP 8.1+
+
 ## 2.10.0 (development)
 
 * Require Wikibase DataModel 8.x or 9.x
diff --git a/composer.json b/composer.json
index 38ce6d85..3aa5efbd 100644
--- a/composer.json
+++ b/composer.json
@@ -31,15 +31,16 @@
 		"irc": "irc://irc.libera.chat/wikidata"
 	},
 	"require": {
-		"php": "^7.0|^8.0",
-		"wikibase/data-model": "~9.0|~8.0",
+		"php": "^7.4|^8.0",
+		"wikibase/data-model": "dev-master#cbbdfcb13e026357f7d441b9c901f06263304e46",
 		"serialization/serialization": "~4.0|~3.1",
-		"data-values/serialization": "~1.0"
+		"data-values/serialization": "~1.0",
+		"wikibase/data-model-services": "^5.3-dev"
 	},
 	"require-dev": {
-		"data-values/geo": "~4.0|~3.0",
-		"data-values/number": ">=0.1 <0.11",
-		"data-values/time": "~1.0|~0.2",
+		"data-values/geo": "^4.4",
+		"data-values/number": "^0.12.1",
+		"data-values/time": "^1.1",
 		"phpunit/phpunit": "~8.0"
 	},
 	"suggest": {