Firmware compatibility <10.2.x

We just bought an AP with firmware 10.3.x and SM with fimware 10.1.1.
After installing them we found out that firmware 10.2.x or higher is incompatible with previous versions.

This is a serious problem, because we must now upgrade ALL SM before upgrading AP, and during that time some of the SM will remain unable to connect.

PMP100 firmwares are very tolerant with different versions, helping upgrade.
What can we do?

Hi we have at the moment the same Problem. We have upgraded our AP C400 from the SW Version 9.5 to 10.3.2 and we have the same Problem. The SM with a lower Software Version don’t see tha AP any more.

Any Ideas or better Solutions?