We have updates some time ago to 11.5.30 on Debian 7.11.
We had problems like that it suspended almost all sites without any reason.
We have fixed that.
No we have problem that on reseller plans and on admin account plans customising one site changes all sites
that use that plan. Even locked plans.
Also made new plan after login to reseller account and it did also the above.
Something is wrong in the psa database.
This needs to be fixed before upgrading Plesk.
We had problems like that it suspended almost all sites without any reason.
We have fixed that.
No we have problem that on reseller plans and on admin account plans customising one site changes all sites
that use that plan. Even locked plans.
Also made new plan after login to reseller account and it did also the above.
Something is wrong in the psa database.
This needs to be fixed before upgrading Plesk.