You've heard this correctly, Feren OS's Linux Mint Repositories can now be easily upgraded to those of Linux Mint 19.1 Tessa, meaning that Feren OS can now have Cinnamon 4.0, Nemo 4.0, and all the other changes for non-Feren-OS components reflected onto its experience.
Updating is as simple as can be, just update 'feren-os-ppa-settings' to the latest version, Refresh the APT Cache by hitting 'Refresh' in Update Manager, and then update everything as the Mint 19.1 Repositories should then take effect the moment feren-os-ppa-settings is installed and the APT Cache refreshed.
Anyway, since it's simple enough to update, let's see what has changed:
The Cinnamon Desktop has received a version bump from Cinnamon 3.8 to 4.0, making the desktop feel more snappy than before, as well as introducing some pretty major changes to theming under the hood, meaning that people using themes such as Windows(R) XP, Vista, 95, 2K, macOS(R), Mac OS X(R), or Ubuntu will notice that their panels have become taller after the upgrade. This is because of the fact that the old method for making the panels smaller has since been removed in the 4.0 Update, and in place of this Themer themes have been updated to make use of the new panel-icon-sizing options, as well as setting panel heights to be the smaller panel heights that they used to be from now on. If you have a taller panel, it can be fixed by simply re-choosing a theme in Themes, or by going into Panel Settings and configuring these settings manually until you have a panel height and icon sizing that you prefer for the panel(s).
As well as this, Cinnamon 4.0 introduces Grouped Window List, an official applet that behaves a lot like IcingTaskManager and also supports configurations for IcingTaskManager too. This means that in Feren OS, IcingTaskManager has now been removed due to no longer being needed, and has been replaced by Grouped Window List. Don't worry, however, your pinned applications should transfer over to Grouped Window List automatically the next time you log into the desktop after the Mint 19.1 update. Furthermore, MessagingMenuV3 got removed too, after being phased out of usage in the themes and configurations, due to being useless by default.
Nemo has also seen a similar version bump from 3.8 to 4.0, giving it all the improvements made to Nemo for Linux Mint 19.1, which can be seen here. Other than that, nothing much has been changed for the Feren OS Customisations on Nemo...
Feren OS Customisations:
There has been a few updates made to the Feren OS Experience alongside the LM 19.1 Update:
- The default settings have received some tweakage to remove depreciated settings, add new configurations to the new settings brought in by Cinnamon 4.0, and introduce new sounds for Login and Logout (you might need to manually set the login screen sound to /usr/share/feren-os/sounds/login.ogg for it to take effect).
- The Feren OS Themes got updated to theme the Grouped Window List applet, however other themes that aren't made by The Feren OS Developer might or might not have proper theming for Grouped Window List yet.
Themer got some major updates to tighten up some security issues on it, as well as adding support for 'warnings' (messages logged and displayed when applying a theme that uses depreciated theme settings), and Cinnamon 4.0's new Panel Icon Size settings. All the '-themer' packages got updated so that they bring in the latest versions of the themes to be better optimised for Cinnamon 4.0, and for Cinnamon 3.8 users Themer also received support for automatically swapping out Grouped Window List with IcingTaskManager (which still exists for them) when applying these themes that are optimised for Cinnamon 4.0. Finally, because of the new 'warnings' feature, if you apply an outdated theme after using Themer, you should get a warning about it after the theme has been applied, so you'll easily know when a theme is out of date.
Overall, enjoy the updates to Feren OS brought by me and Linux Mint 19.1, and thanks for choosing Feren OS. Also, if you haven't got Feren OS yet, wait out for a little while if you don't want to have to update to Mint 19.1 yourself via Update Manager, as a New ISO Update is coming out for x32, x64 and 'KDE Experimental' very soon to bring in the Mint 19.1 / Cinnamon 4.0 changes, tweaks, and more out of the box...
It's great making something for the community that might become quite big and remain for a very long time to continue serving the community and helping Linux as a result.