Update dates based on latest expectations

source/v5-0-announcement/index.html.md.erb

@@ -58,7 +58,7 @@ We've tried wherever possible to minimise the impact of the changes service team
 
 ### When it will impact your teams
 
-Based on current estimates, we expect a test version (or pre-release) will be ready for teams to test between July and September 2023. This gives us an opportunity to receive feedback and make necessary changes before a full release. We expect that the full release will be ready between October and December 2023.
+A test version (or pre-release) will be ready for teams to test at the end of October 2023. This gives us an opportunity to receive feedback and make necessary changes before a full release. We expect that the full release will be ready between November and December 2023.
 
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