The ChangeLog for all releases from 1.0 (2006-06-16) up to 5.0.0 (2024-11-10)
is available here:

https://github.com/tesseract-ocr/tesseract/blob/64eab6c457b2337dd690746a5fde5c222b40d5f8/ChangeLog

See https://github.com/tesseract-ocr/tesseract/releases for the latest release notes.