It's not on MDL, we are on MDL, KMS is originally developed here, we only promote tools that are supported here. And it's not as well known as you think.
Thread is resumed but microsoft pulled back iso's.. thread needs to give status info about this at first page
MSFT didn't pull back anything else than the WU and other ESD upgrade methods, all iso's/ESD's and UUP files are still available, according the @mkuba50 his MVS Checksum info, they removed the 1809 info.
is "17763 RS 5" worth the trouble? Will the re-release be forced for users on RS4? Is RS 5 stable? I am asking because i don't want critical bugs inside my production PC...
It depends on what version of Win 10 you have ? Home, Pro, etc. On Pro you can delay for up to 365 days in Advanced Options.
17763.XX is still being tested in the Insider Program (Slow Ring, & Release Preview Ring). It is up to Microsoft as to when it will be released to the General Public. As far as being stable ? It depends on what PC you have & your Hardware.
If you use Windows Server, you can delay forever as there are no forced updates, only if you install it from DVD or USB manually, which is alot better and can avoid "data loss" due to forced updates.
I confirm that on my hardware (i7-8700k, Nvidia gtx 1080 Ti , Samsung pro nvme) all my applications like (Adobe premiere, Visual studio , office ...) works with no problems. just some cosmetic glitches or flash with Explorer. Everything else is fine.
I dont think u understand what im saying im testing 18262 one computer and 17763 in another but the only CU I have receive is17763.55 WU in showing me anything else and I see u posted in your OP how to install it manually so I sk if the MS WU s broken and is not sending it down.
The update you are expecting for 17763.104 is only released in the RP and SLOW ring, not in the fast ring, so make sure your 17763 install is signed in at the RP or SLOW ring, not the fast ring (iirc you mentioned it was set to FAST ring).
50% brightness bug - occur laptop, notebook or desktop PC too? I know it already fixed in build 18262, and probably will be fixed in October 2018 update (in build or cumulative update) when it will be GA.
You need to join insider as slow or release preview on the 17763 machine in order to get the 104 update, because 17763 is not released to the public at this time, only to insiders.