Create README.md

Signed-off-by: David Rotermund <54365609+davrot@users.noreply.github.com>

admin/linux/fedora_dnf_version_upgrade/README.md

@@ -0,0 +1,49 @@
+# Updating to the next version
+
+## Top
+
+Questions to [David Rotermund](mailto:davrot@uni-bremen.de)
+
+Before starting, you need to install the dnf-plugin-system-upgrade package. 
+
+```shell
+dnf install dnf-plugin-system-upgrade
+```
+
+After that, this is normally enough (example for 37 -> 38):
+
+```shell
+dnf -y system-upgrade download --refresh --releasever=38 --allowerasing --best --skip-broken 2> error.log ; dnf system-upgrade reboot
+cat error.log | grep -v "^No match for group package" | grep -v "^Error:"
+```
+
+However, you might encouter problems like: 
+
+### Remove obsolete packages 
+
+We can analyse the error.log file: 
+
+```shell
+echo "Check if these packages can be deleted:"
+cat error.log | grep -v "^No match for group package" | grep -v "^Error:" | grep "does not belong to a distupgrade repository"
+```
+
+```shell
+Check if these packages can be deleted:
+  - jack-audio-connection-kit-example-clients-1.9.21-3.fc37.x86_64 from @System  does not belong to a distupgrade repository
+```
+
+Now we can try to remove the obsolte package carefully(!!!): 
+
+```shell
+yum remove --noautoremove jack-audio-connection-kit-example-clients
+```
+
+After that we can try to run the upgrage again: 
+
+```shell
+dnf -y system-upgrade download --refresh --releasever=38 --allowerasing --best --skip-broken 2> error.log ; dnf system-upgrade reboot
+cat error.log | grep -v "^No match for group package" | grep -v "^Error:"
+```
+
+