If you are happy with the last release version (v1.08) then there is no need to upgrade. Your PBEM games will work fine without upgrading, no one is being forced to upgrade from v1.08 to the v1.09 betas.
However, I'm afraid that if you are using the beta version of Strategic Command (v1.09.xx) you do need to upgrade to the latest version to keep playing PBEM, otherwise bugs might occur due to players using different data sets.
This is because there are 2 PBEM servers, 1 for official releases and 1 for betas being developed
I am sorry for the inconvenience
Fair Enough, I suppose, do we have an ETA on the hotfix as I have a game on hold that I would like to continue losing
'There is not, nor aught there be, nothing so exalted on the face of god's great earth, as that prince of foods. THE MUFFIN!!!'
Frank Zappa (Muffin Man)