Update to 5.1 is not offered while checking for updates

Manually checking for updates from within LibreOffice 5.0.3 via menu offers only updates to 5.0.4 but not 5.1.x.
5.1 is designated as stable:

LibreOffice Fresh is the stable version with the most recent features.

If 5.1 is stable shouldn’t it be offered as an update?

Tested on: Windows 10 64x

Refer to my answer to Q65745 .

Your version is part of ‘Still’ (which is why you got offered 5.0.4, also in Still), whilst 5.1 is part of ‘Development’.