Is it just my intense curiosity where did all the updates go, or there are really no updates since 20th of APRIL?
Also, I have installed proprietary NVIDIA driver and have met all of its requirements, for example kernel source. I added source repository, and, maybe, possibly, that caused me to see no updates for so long? I’ve checked logs on the repo and saw that last time the changelog file was modified after 20th of April. So they do update something. I’m scared. I don’t want to reinstall the whole system again for like 20th time already. Thanks in advance
Hi and welcome to the forum 
Well Tumbleweed is a rolling release, so you need to do a distribution upgrade, not an up as the updates repo is only for emergency packages for example a security issue and can be deployed quicker than the next release…
So, for example if you use a third party repo (packman) you would do an install, then;
zypper -vvv dup --from 'packman'
This is to do a vendor switch the -vvv adds some verbosity so you can see what it’s doing, then once switched the normal command after a new release would be;
zypper -vvv dup --no-allow-vendor-change
This should then update you system to the next release (currently 20170226).
You need to keep an eye on the Factory/Development Mailing List, eg;
https://lists.opensuse.org/opensuse-factory/2017-04/msg00994.html
Ref 1: https://lists.opensuse.org/opensuse-factory/
Ref 2: https://en.opensuse.org/Communicate