Qt 4.8.4 in experimental.

Since a few days we have Qt 4.8.4 (4:4.8.4+dfsg-3) in some archs of the experimental Debian archive. This release allows Qt4 to coexist with Qt5 while avoiding FTBFSs of current Qt4 packages in the archive.

So if you maintain a Qt4 app and want to check how it works with 4.8.4, you should be ready to go.