updating fieldtype version

EE 2.1 changes broke parts of one of my custom fieldtypes such that I need to change how the data is stored in the database. I’m looking for a way to run some “update” code after the user has updated my third party code to the next version. The fieldtype API has install and uninstall functions, but these don’t appear to be triggered when the version changes. I can’t find any evidence of an update function. I can certainly do something hack-y but I’d rather go with best practices if there are any here.

Also weird… when I change the version number in my ft.my_fieldtype.php file it updates accordingly on the Add-Ons -> Fieldtypes page in my EE 2.1 CP… however the corresponding record in the exp_fieldtypes table does not update unless I uninstall and reinstall the fieldtype (which of course wipes out any settings and such that might’ve been stored so that’s not really a good idea).

Bugs? I’m doing it wrong? Who knows!