I tried installing it by adding it to my project, by installing through the backend installer, and by using Artisan. All methods failed for me. I'm on OCMS 3.5.1 if that helps.
- Your requirements could not be resolved to an installable set of packages.
- Root composer.json requires deividas/announcementbar-plugin^1.5, found deividas/announementbar-plugin[dev-master] but it does not match the constraint.