Endless OS ordinarily features an automatic update mechanism that can smoothly take you from any old version to the latest, even when major changes are made. However, Endless OS 3 was an exception here, we really changed the fundamental composition of the system, such as the adoption of Flatpak as our app technology.
Due to the enormity of the changes throughout the system, and the fact that the old applications format used in 2.x will no longer be supported, previous Endless OS users who want to use Endless OS 3 will need to upgrade their systems semi-manually. Please note that this upgrade may not be the best option for all users, so read the benefits and limitations below carefully before deciding whether or not upgrade to Endless OS 3.
If you do not upgrade to Endless OS 3, your experience will remain as it is and will be regarded as unsupported. You will not receive new apps or updates. We highly encourage users to upgrade.
Benefits of Endless OS 3:
When you are ready to upgrade to Endless OS 3, follow these steps:
Update to the latest 2.x version. You can do this by going to Settings > Details > Check for updates now.
Back up all of your files, just in case.
Go to Terminal and enter the commands as below:
rm -f eos-upgrade-eos2-to-eos3 wget https://raw.githubusercontent.com/endlessm/eos-customer-support/master/eos-upgrade-eos2-to-eos3 sudo bash eos-upgrade-eos2-to-eos3
Enter your user password when asked, read the warning message displayed, and type "y" followed by the Enter key whenever you are prompted to proceed.