How to install extensions from past versions of 3D slicer

I have Slicer-4.8.0-win-amd64 on a windows 10 system. I can no longer interface the extension-manager. I have a very specific hierarchy design in a human trial and need to keep version 4.8.0 running on a new computer but I can not get Sequences or SlicerIGT extensions for some reason. Are these extensions available still for Slicer-4.8.0 via hard disk?

The expertise in my group is no longer avialble to redesgikn the hierarchy in the newest version of 3D slicer.

See instructions how to download old releases of Slicer and extensions for it here. You can install a downloaded extension package by selecting Install from File from the tools menu in the Extensions Manager.

@jcfr As far as I remember, you implemented a backward compatibility layer in the new extensions server. Isn’t it supposed to make extensions manager work in Slicer-4.8?