We are doing router upgrades over the next few days. As usualy these should have little or no impact, but have been seen to cause a few seconds of impact on routing on some occasions and more so on IPv6. Last time we did upgrades there was a PPP restart on many TalkTalk lines. We think we know the cause of that and so will be doing upgrades in a slightly different sequence to see if that can be avoided. We do not do all routers on the same day, and so this will be over a number of evenings. There will be LNS upgrades over night as well to bring LNSs up to the latest release of code as well.
The main routers have all been upgraded. There still some over night LNS switch overs to be done over the weekend to complete the upgrades.