Plugins don't have to choose. If the API is changed, all plugins
compiled with it use this version - the version they were compiled with.
Sounds weird. What would the version be for then?
Besides, there's 0x100 plugin, which is supposed to be compiled with
version 0x0100 (I guess this means 1.0 and hence all the related renaming is
done).
The sql_acl side also checks the version and uses the API accordingly.
But after looking at the second patch I think that you didn't introduce
any changes in the API, so the version doesn't need to be increased at
all.
I made -- now hash_password is called for empty password, which wasn't
expected by old plugin.