It looks like double posting the news, but it is rather an update to the previous one.  A new PTR testing schedule update has been released.  Blizzard needs you to type /combatlog before engaging these bosses and then submit the log to them. The log may be found in your WoW folder within the logs folder. The numbering matches the date. To disable logging you can type oncreen again: /combatlog.

Blizzard Quote:
Here’s the current schedule for Ulduar PTR testing. We’re currently in a mild holding pattern while we wait for a new PTR build with updated changes to most all the bosses, Mimiron, Auriaya, more loot, etc. As a reminder, this schedule could change further depending on build status.

On the North American test realms:

Mimiron – Friday Night, March 13, starting at 7pm EDT/4pm PDT.
Hodir – Saturday Night, March 14, starting at 7pm EDT/4pm PDT.
Flame Leviathan – Sunday, March 15, starting at 2pm EDT/11am PDT.
Ignis the Furnace Master – Monday Night, March 16, starting at 7pm EDT/4pm PDT.
XT-002 Deconstructor – Tuesday Night, March 17, starting at 7pm EDT/4pm PDT.
Kologarn – Wednesday Night, March 18, starting at 7pm EDT/4pm PDT.

On the European test realms:

Mimiron – Friday Night, March 13 at 19:00 CET.
Auriaya – Saturday Night, March 14, at 19:00 CET.
Flame Leviathan – Sunday Night, March 15, starting at 19:00 CET.
General Vezax – Monday Night, March 16, starting at 19:00 CET.
Thorim – Tuesday Night, March 17, starting at 19:00 CET.
Freya – Wednesday Night, March 18, starting at 19:00 CET.

This schedule could change at a moment’s notice due to server, bug, or patch status. I’ll try to keep everyone informed as much as possible. Ulduar and the bosses to be tested will remain also open a variable length of time. How long they stay open depends upon a host of factors including designer availability, bug status, etc.

We’re very interested in seeing combat logs and parses for all raid testing on the PTR.