Version numbers are not always what they are cracked to be. Windows 10, for example, has kept the version at 10.0, with only incremental build numbers which are prefixed by the month and year.
Google is a little different. Talkback has undergone major evolution even in minor releases. Yet in the last few ones from 5.0 up to now, the changes to Talkback have refined much of what we experience. In 5.0, screen dimming, and in 5.1, abilities q export custom labels and more intelligent interaction handling removed many pain points for the user.
With 5.2, perhaps one of the largest ones is addressed. Have the accessibility developers behind Talkback made the right choice with the redesigned sounds? For the first time, there is a mobile screen reader which allows for desktop-quality granular control. Is this useful? Be sure to check out this article to get the full Changeling of to this release.