Forti AP - JOIN REQ from WTP with unsupported hardware is denied

[technik]

We have several AP's across our sites with a selection of different fortigates as gateways. 110C, 100D and 2 x 80C

All AP's are either FP-221b or FP-221C

Recently reviewing the firmware images have updated the gateways to v5.0,build0323 (GA Patch 14) and now the FP221C are not connecting with error JOIN REQ from WTP with unsupported hardware is denied. I'm uk based and don't see why the FP221C should not be supported, as they were provided as alternatives to the 221b by our supplier.

Any help / info would be appreciated.

[technik]

Should of said. 

Fortigate - 110C previously and now back on 4 Mr3 Patch 19, attempted upgrade to v5 build 323

2 x FP221C-v5.2-build0234

Fortigate 80c previously and now back on 4 Mr3 Patch 19, attempted upgrade to v5 build 323

2 x FP221C-v5.2-build0234

Ive just looked through a lot of the revision notes and I could not find any that actually support the 221c

[Toshi_Esumi]

Well, I'm not sure how FAP221C w/ 5.2.3(build0234) works with FortiOS 4.3. When you check through FortiOS's release notes the supported version of FortiAP firmware for 5.2 started only FortiOS 5.2.0. So I can see it should work if you upgraded FortiGate(FortiOS) to 5.2.x.