If you don’t know what version of CodeIgniter you are currently running, and assuming that Composer was used to install CodeIgniter: you can get it by running the following command line:
genie@en-03:/var/www/busylines.co.za/web$composer show | grep codeigniter
codeigniter4/framework v4.4.3 The CodeIgniter framework v4
The current version is v4.4.3.
All the best of luck.