Your link is people complaining that the source isn't being released fast enough... and Synology has told them it will be put on SourceForge when they're ready. There seems to be a lot of precedent for that to go how they said it will.

There's also an independent community that facilitate installing and using it on your own hardware including the latest version that's still waiting on the source dump.

Sure, no one needs that source code anyway because they are not adding anything of value. But if they are not complying the GPL license they are legally not allowed to use the GPL projects.

As an example for their relationship with upstream, they market the btrfs feature (https://www.synology.com/en-global/dsm/Btrfs ) but don't have anyone working on btrfs (and btrfs could surely need the help). I can see one patch set from them which hasn't made it into mainline ( https://patchwork.kernel.org/project/linux-btrfs/list/?submi... ).

> And since they haven't published the latest versions they are in violation of the GPL.

There are a few ways that they can comply with the GPL without posting the source on the web.