Apple devices failing to connect after software version upgrade

[Beardo]

Problem:

Reports of Apple devices no longer being able to connect to WiFi after upgrading software version

Controller:          MSM 460

Access Points:   (majority) HP 430’s and HP 422’s

Original software version: 6.0.2.2

New software version: 6.5.1.0

2 VSC's both set for WPA and WPA2 Wireless Protection

• One using a preshared key
• One using RADIUS authentication

Soon after the software update we received reports of Apple devices having trouble connecting to some of the access points.  We were able to confirm this behavior with test Apple devices.  

It is important to note:

• Some users reported their Apple devices connecting fine to the affected AP's
• Several Apple products were reported to have this problem (iPhones, iPads, and Macbooks)
• Device firmware version of affected iPhones and iPads spanned from the newest (8.3) to older versions (7.X)

With the new software version on the controller the "Dashboard" tab was showing an "Association Success Ratio" of around 76%.  Looking at corresponding Event Logs on the AP's around the timeframe that Apple devices were trying to connect and failing we saw a specific event keep popping up.

Type: Information mismatch in received EAPOL key frame 

Description: Received EAPOL key frame with a mismatched information element from client (mac='XXXX') on interface (value='YYYY)"

A call was placed to HP Support with logs and configuration settings sent to them.  After several days of troubleshooting and suggested configuration changes we were able to finally identify the problem and resolve the issue.

Resolution:

Change the following setting on the Controlled AP's:

Radio management -> Radio configuration -> Advanced wireless settings -> Client restriction: Disabled

Previously it had been set to "802.11n only".  Once the setting for Client restriction was set to "Disabled" Apple devices started connecting just fine and within 24-48 hrs our "Association Success Ratio" was up to 100% with only a handful of failures per hour (unrelated reasons).  I was told by HP Support that this was a misconfiguration issue as having Client restriction set to "Disabled" and having the VSC's set to "WPA and WPA2" caused the problem even though this configuration was NOT a problem pre-6.5.1 code