ac2 downgrade from 2.1 ga3 -possible

[UbiUserISP]

I need to downgrade from 2.1.ga3

to ac2 that supported 5.5.x formware

Due to issues on old xm devices,  with 5.6 and 6.x

I use restoring windows postgres database via  postgresadmin.

Any ideas?

Regards

[Skipper0815]

No not possible.
Start over with a new database.