This version has been released.  As there are a number of reports that it causes problems with third-party modules, the recommendation is that you NOT upgrade sites to 5.4.0.

Thank you for a great site, it's a tremendous resource!

I have been advised by a module vendor to wait until DNN 5.5 is available before we upgrade (We are currently running DNN community edition 4.9.4). Any idea when that might be?
Thank you,
Matt Crowshaw

It could be that their module has problems with DotNetNuke 5.x.

Otherwise, I really don't have a good answer.  DotNetNuke 5.x has been with us a good year, now.  I think that it's been pretty good for at least 6 months.  I didn't have that many problems with the early 5.x releases either.

DotNetNuke 5.5 is going to introduce lots of new functionality related to content localization.  While this is a great step forward, I wouldn't be at all surprised to see some issues when that reaches general use.  If 5.4.4 is relatively stable, that might the the version to have for a while as the new features in 5.5 get stabilized.