only way to downgrade your database is to restore the db backup made before you upgraded…  then load up the version of the simple pres forum plugin…  there is no programmatic way to downgrade…

Mr Papa said
only way to downgrade your database is to restore the db backup made before you upgraded…  then load up the version of the simple pres forum plugin…  there is no programmatic way to downgrade…

That’s a bit of a problem, I didnt make a backup because I didn’t expect I’d need it because the upgrade worked all perfectly fine on a duplicated wordpress.

Surely if there’s a way to upgrade, there’s a way to downgrade… what exactly changes during an upgrade?

The only one I have is from 01:00 this morning, which is missing posts…

Can I partially downgrade via a backup without losing posts?

posts cannot be recreated without data, so not really…

have you determined what is causing the issue with wp 4.3 on your site?  you could try removing the downgrade check and see if you have issues there…  in sp-load-install.php, find and remove or comment out this code:

# downgrading? not good
if (SPBUILD < $current_build || version_compare(SPVERSION, $current_version) == -1) {
    sp_no_downgrade();
    return;
}

but please realize this is unsupported and may not work…  a better choice would be to resolve the 4.3 issue on your site…