write API character count fix release notes (#272)

Author: shirgoldbird

docs/resources/roadmap-and-release-notes.mdx

@@ -11,6 +11,12 @@ rss: true
 - `v3/languages` endpoint with improved language code handling and additional functionality
 </Update>
 
+<Update label="March 2026">
+## March 24 - Write API Character Count Fix
+- Fixed an issue where some [DeepL API for Write](/api-reference/improve-text/) requests under-counted usage.
+- All characters in Write requests are now correctly counted for billing and reporting purposes.
+</Update>
+
 <Update label="February 2026">
 ## February 18 - Additional Languages in `v2/languages`
 - New languages added to the [v2/languages endpoint](/api-reference/languages), bringing totals to **101 source languages** and **106 target languages**.