I think that it is better to allow the developer to manually upgrade the development tool when appropriate (or even install the new version in a new folder).
Well, I think auto-updating doesn't have to be automatic, but to control actual versions of B4X products (I work with all three) would help if the program:
Could check the installed and new version and popup a message
Had an option to Check actual version (for example at Help--> About menu option --> Version installed vs actual version)
At this menu, could display dialog with the update's info or a link to the forums post that explain the new version updates (or to the version history updates)
If possible, a link to the update file B4X new version (maybe this is more difficult because the update's actual distribution is by mail)