How to make multisite between Joomla 1.5 and 3.3?

Question

Joomla

I ran into an unexpected problem.
It is necessary to make a multisite between Joomla 1.5 versions and 3.3
Unfortunately, I installed the MightySites module necessary for this, which made the user base available on both sites.
BUT.
A user registered on the old version of Joomla can easily log in to it, but if the same user logs in to Joomla 3.3 version, then in the database his password is converted to a newer format, which allows you to log in to the new one, but it stops working on the old one .
Has anyone encountered this problem, and is it possible to solve it somehow?
So that the user can both log in and register there and there without any problems.
p/s - Do not offer to change Joomla versions.

Answer 1

Then I can suggest patching one of the versions to support the password format of the other.