Update to latest minor version
First you need to upgrade Nextcloud to the latest minor version of Nextcloud. When that’s done, you can upgrade to the newest major version.
Prepare apps for latest version
Before you upgrade to a new major version, you need to make the following changes to your appinfo/info.xml
to allow the next version of Nextcloud for all of your apps. So for Nextcloud 26 you need the following changes to the file:
<dependencies>
<nextcloud min-version="23" max-version="26" />
</dependencies>
To make the changes to all apps at the same time you could go to the root of your Nextcloud installation and run the following command:
sed -i -e 's/max-version="25"/max-version="26"/' apps/*/appinfo/info.xml
Here you can just change 26
to the newer version of Nextcloud.
Upgrade to latest major version
After this you can go back to the web interface and update to the latest major version of Nextcloud.
Read more over at Nextcloud!