Cutting back to the bare minimum it seems, the full annoucement and merger details can be seen at the offical forums here.
More information.As you probably have heard, we merged the two US servers 'Bloodspire' and 'Hyperborea' on 7th of January. We monitored the new server closely and can confirm that the merge was going very well and without issues. So we will now proceed with the next steps for the other servers.
Firstly, we present you the list of the planned servers to be merged (see below). We will proceed with merging next week and the specific date and time as well as the expected downtime will be announced soon too. As a general information we can already say that the plan is to merge all EU servers in one go and all US servers in another go.