How do I know what I have tested?

I already have used a test script for making release tests of a tool version.
Now I want to adapt the test script for a new tool version.
The test script is referenced by test cases which are used in older test case execution records.
How do I make sure that I still know what was the content of the test script in older test case execution records?
I still want to know what exactly I have tested to release older tool versions.
For me a revision management for all items like in Foswiki seems to be missing. The test case exeuction records have to reference a certain version of the test case and the test script which were used in the record.