PIX 515E's on both ends, one with version 7 of PIX IOS, and one with version 6 -- also, there are no firmware upgrades to the PIX running IOS v6.
IPSEC VPN drops completely in a completely random fashion, and it comes back up after the SA's are cleared. Is the best step at this point to upgrade the v6 PIX to all current firmware and PIX IOS versions? What would I look for after the upgrades if the issue were not resolved?