Everywhere is recommended to upgrade only one release version at a time, because only one at a time is “supported”. This thread is to report there is apparently little danger in skipping. I haven’t kept track, but I’m guessing out of my 15 current 15.1 installations, 5-6 times I upgraded directly to 15.1a or 15.1b or 15.1 final from releases older than 15.0. With 15.0 I jumped from as far back as 13.1. Yesterday I upgraded a TW installation that hadn’t been upgraded in over 7 months. An hour ago I finished another hiccup-free jump, this time from 42.2/KDE3 to 15.1/KDE3, with ancient Radeon X600 (1002:5b62) video.
My technique includes disabling all optional repos, “solver.onlyRequires = true” and “commit.downloadMode = DownloadAsNeeded” in /etc/zypp/zypp.conf, then beginning the upgrade by preceding zypper dup with the same script I use for preceding normal updates, designed to upgrade the package management stack before anything else:
#!/bin/sh
# /usr/local/zypstart
zypper -v in --download-in-advance zypper libzypp libsolv-tools rpm openSUSE-release
zypper -v in --download-in-advance device-mapper dmraid glibc multipath-tools mdadm systemd udev
Most times when starting zypper dup I strike g then home and peruse the plan, quite often aborting in order to add or remove locks and/or selected packages.