Way back in mid-December I wrote about how Service Pack 2 had been released. As a major update, appearing just before the Christmas holidays, it was an option that seemed a little too risky to try and squeeze in alongside our phase of mass-migrations. Then, last week, it was announced that the first roll-up for this service pack has now been released containing a scarily long list of fixes and bugpatches. I guess waiting for a little while was no bad thing…
There was also a note from the Exchange Team on Friday that even this update has introduced a change which might have affected us. SP2 RU1 package changes the user context cookie used in CAS-to-CAS proxying. What they describe as ‘An unfortunate side-effect’ is incompatibility between SP2 RU1 servers and other any other versions. It seems that earlier versions of Exchange do not understand the newer cookie used by the SP2 RU1 server. The effect? Proxying from SP2 RU1 to an earlier version of Exchange will fail with the error:
Invalid user context cookie found in proxy response
The size of our environment (and our two-hour maintenance window) make it difficult to undertake major updates except on a rolling basis over several weeks. The solution of ‘simply’ upgrading all servers to SP2 RU1 to avoid this problem might be a more involved task in a large environment than the article suggests.