Citect SCADA 2018 V8.1 - O/S compatibility

i have 2 only Citect SCADA 2018 V8.1 servers running on WIN 7, all my workstations are running same on WIN10 without issue for around 3 years now.

next year the servers will be upgraded, i know Citect SCADA 2018 V8.1 is listed as compatible for WIN10 only but when i buy new servers its likely they will be WIN 11 O/S.

this means i will have a hardware and software upgrade to do. as i have redundant servers  is there a white paper or procedure to do an online upgrade i can follow for this?

also (although not recommended) has anyone used Citect SCADA 2018 V8.1 on WIN 11 temporarily while upgrading?