Because the Launcher only keeps the least buggy version of each release.
Hi Uriel,
You can read that as 5.5 hotfix version 4
Although, it is very strange that the hotfix versions for UE4 are not listed (For example, it should show 4.26.2 instead of 4.26.0)
If you’d want to trouble-shoot this, try changing your launcher language to english and seeing if the correct hotfix versions for UE4 are shown.