Due to the increasing size of the archive repositories as old releases get moved to them, and the fixed disk space of the repository servers, the archive repositories will be moving to http://archive.webtatic.com/ from February 1st, which is already serving them.
This means from February 1st, they will no longer be on the http://*.repo.webtatic.com/ servers.
This affects the following repositories:
It will not affect the el5/6/7 repositories or the testing repositories.
What you need to do
Nothing, except if you're intentionally mirroring the archive repositories.
Traffic from these repositories will be redirected to the archive domain's URLs, so unless you are mirroring the archive repositories, your servers will continue to be able to download from the archive (if you have enabled it).
If you are mirroring the archive repositories at the moment, and would like to continue to, please contact me at firstname.lastname@example.org so I can understand your use-case for it, and whether to sort out another arrangement.