We came to know from the Linux Mint monthly (April-2019) newsletter, the Linux Mint team reported that Linux Mint 17.x has reached the end of its supported life.
After 5 good years of service, Linux Mint 17.x (i.e. 17, 17.1, 17.2 and 17.3) reached “End Of Life”.
Although the repositories will continue to work they will no longer receive security updates.
Linux Mint 17, 17.1, 17.2 and 17.3 will be supported until 2019.
If you are running Mint 17.x, you can install Timeshift from the repositories, prepare system snapshots and plan to upgrade to Mint 18
If your version of Linux Mint is still supported, and you are happy with your current system, then you don’t need to upgrade.
However, i would advise you to go for the upgrade if you are running the Linux Mint in the latest hardware.
It will give you an additional benefits.
Running an operating system with latest release is a good practices.
It can solve some of the outstanding issue that you are currently facing.
As updated by Linux Mint team, there is no security updates will be reased for Linux Mint 17.x.
So, better to go for the upgrade.
Prerequisites For Linux Mint 17.x Upgrade
The upgrade tool only upgrades Linux Mint 17.3 Cinnamon, MATE or Xfce edition.
If you are running Linux Mint 17, 17.1 or 17.2, you first need to upgrade to Linux Mint 17.3 using the Update Manager.
The KDE edition isn’t upgradable (Linux Mint 18 KDE will use a new and different desktop called Plasma).
How To Upgrade Linux Mint 17.x To 18.x?
Using the Update Manager, click on “Refresh” to refresh the APT cache and apply all level 1, 2 and 3 updates.
Install the upgrade tool
apt install mintupgrade
Check the upgrade
Then follow the instructions on the screen. This command temporarily points your system to the Linux Mint 18 repositories.
Download the package upgrades. Make a note, this command doesn’t actually perform the upgrade itself, but just downloads the packages.
Finally apply the upgrades.
Refer the following article, if you are still having an issue for upgrading Linux Mint 18.