Upgrading to 2.1 Scheduler using Anki 2.1.44 then downgrade to 2.1.40

I want to upgrade to scheduler v2.0 without resetting learning cards. I am thinking of installing anki 2.1.44 (this version can upgrade to scheduler 2.0 without resetting cards), upgrading to scheduler 2.0 then downgrading to 2.1.40. Downgrading because some addons are not working on new version.

Will it cause any issues with the scheduler ?

not at all, just remember to “downgrade and quit” (2.1.44 → 2.1.40) on profile tab, and you are good to go