Availability dates for things announced at Build
Today we've learned about various things that will be become available in the coming months, so I wanna summarize them. Please comment if you got additional or different information!
Windows Phone 8.1 (consumer release)
"Coming months". All existing Lumia devices will get the update "this summer". Seems like all WP8 devices will get the update.
Windows Phone 8.1 developer preview
"First part of April". According to reports from WPCentral, MS plans to release it on April 10th. Anyone can register for the developer program for free to get access to that preview.
It will be a US only, "beta" tagged version at first. The final version will be avilable in the US, the UK and China in the second half of this year, and in additional countries in 2015.
Windows 8.1 Update
April 8th, through Windows Update.
Windows 8.1 Update for developers
Nokia Lumia 930
Europe in June, then Asia and Middle East, other regions (except US) throughout the summer.
Nokia Lumia 630
May, beginning with Asia and Europe. (Latin America in June.)
Nokia Lumia 635
July (US). "Broadly available" (no detailed information)
Touch optimized Office apps for Windows and Windows Phone
No information, "work in progress".