I'm using Whonix Gateway and Workstation. Recently Arm shows
Tor 0.2.9.9(unrecommended)
(unrecommended is red)
How can I update to a newer version of tor? Is it dangerous to use as it is ?
You should follow the steps outlined on the Whonix Security Guide.
In simple terms, you should only need to run the following commands:
apt-get update
apt-get dist-upgrade
reboot
By the looks of it, 0.2.9.9 is the latest version distributed for Whonix.
Package: tor
Version: 0.2.9.9-1~d80.jessie+1
There have been some bugfixes since then, most prominently CVE-2017-0376 which only affects onion services. The consensus suggests that it's not a recommended client version currently but I don't think it's explicitly known to be unsafe if you're only using it as a client.