After upgrading all (262 of 274, actually, mix of AP350, AP1100, and AP1200) our access points to IOS-12.3.8-JA (I did make sure to put the correct image on each different model of access point), I no have a problem with wireless VOIP clients' connections dropping very frequently.
"regular" wireless data connections seem quite stable and very usable. The negative effect appears to have been only on the wireless VOIP connections. This occurs not only when roaming, but I can be just sitting at my desk, testing the wireless VOIP service, and lose a connection mid conversation, a few minutes after establishing a connection, more than an hour after establishing a connection, seconds after establishing a connection, when I attempt to place a call, etc. Basically, there doesn't appear to be a pattern to the loss of connections.
When the connection is dropped, the client needs to be power-cycled in order to establish a new one. The access point logs next to nothing (though I'm appending what is logged, in case it does help) that I can get any idea of what the problem is with.
What additional information can I provide for someone to be able to advise me on this problem? Thanks in advance for any help. "all" is not entirely true: the IOS upgrade failed on 12 access points, none of which are among those I'm aware are currently causing trouble.