Manga UK have confirmed on their Twitter that tri. Part 1 has once again been pushed back in the UK.
They've announced they are working with Shout on the release of Digimon Adventure tri.
On the positive side, they've confirmed this means bonus content for the UK DVD/BD that was previously unplanned.
There is no news on what the actual bonus content is.
The US version was previously unscheduled, but we knew previously based on comments from Manga UK that due to contractual issues, the US version has to come out before the UK version for Manga to receive the dub.
Since their early announcements Manga UK has been clear the release would be both Japanese and English for their release, which has been the cause of the delays.
The new UK release date is May 22nd.
Shout has not currently announced a US release date, but based on Manga wanting to get their release out as fast as possible, we can reasonably assume it will be immediately before the UK disk.
Based on Manga UKs comments in the past about getting their release out as soon as contractually possible, we're probably looking at a US release around May 16th, although that is just a guess.
Shout has also said they plan to make an official announcement soon.
Update by Marc- Tweaked the news post a bit to add information and move things around a bit.