7962s are certainly supported since version 8.1 of ZoneFlex, and I could have
agreed that code got bigger so remote sites over VPN WAN links might need
to adjust MTU, but not for APs local to the ZD.
Since 220.127.116.11.30 was posted last week, I'd recommend a backup/upgrade of your
ZD and another evaluation of the AP behavior. Be sure to have DHCP and see
that your ZD can ping all the APs. If you still cannot get all APs to upgrade, open
a support case and upload your ZD Debug (from Administer/Diagnostics), with
the Access Points component enabled, and we'll take a deeper look.