diff --git a/README.md b/README.md
index 3d31ea0..fae3827 100644
--- a/README.md
+++ b/README.md
@@ -26,7 +26,7 @@ version 0.8 of this package:
 
     {
         "require": {
-            "data-values/number": "0.10.*"
+            "data-values/number": "0.12.*"
         }
     }
 
@@ -49,6 +49,14 @@ the [Wikidata project](https://www.wikidata.org/).
 
 ## Release notes
 
+### 0.12.0 (2022-10-21)
+
+* Improve compatibility with PHP 8.1;
+  in particular, the new `__serialize`/`__unserialize` methods are implemented now
+  (in addition to the still supported `Serializable` interface).
+  Make sure to also use `data-values/data-values` version 3.1.0 (or later) to keep hashes stable.
+* Remove the `DATAVALUES_NUMBER_VERSION` constant.
+
 ### 0.11.1 (2021-03-31)
 
 * Fix `DecimalMath::productWithoutBC` for products larger than 2^63-1 (the maximum value of a signed 64 bit integer).