Hi Andreas,
Thanks for your reply. I mean:
1. I am using Unilabel 3.6.3 (2019050900) on my Moodle 3.7 version. I am using it in many courses currently.
2. I want to upgrade Unilabel to 3.8.1 (2020022900) on the same Moodle 3.7.
3. As you suggested, I need to copy this plugin into /moodle/mod/unilabel and subplugin.php into /moodle/mod/unilabel/db.
4. My doubt is, can I just copy 3.8.1 plugin files into already existing (for 3.6.3) folder without loosing any previous data? By data, I mean the unilabels I already created in my courses using old Unilabel, i.e. 3.6.3 version.