How to check OS version of Synology NAS Disk Station Manager (DSM)?

Question

How do I check what OS is installed on my Synology NAS?

uname -a informed me that my NAS is:

aarch64 GNU/Linux synology_rtd1296_rs819

..but how do I know what version of the Synology OS it's running? Wikipedia tells me that Synology used to use an OS based on BSD, but today it's "Linux-based". I tried to get the version from all the usual places, but none of these files exist:

1. /etc/issue
2. /etc/redhat-release
3. /etc/release

How do I determine what is OS version of Disk Station Manager that my Synology NAS is currently running via the command-line?

Solution

The file you want to check is /etc/VERSION

bash-4.3# cat /etc/VERSION
majorversion="6"
minorversion="2"
productversion="6.2.1"
buildphase="GM"
buildnumber="23824"
smallfixnumber="4"
packing="iSCSI"
packing_id="1"
builddate="2018/12/25"
buildtime="16:58:15"
bash-4.3#

To determine the latest version of DSM, see their website:

• https://www.synology.com/en-us/dsm