The localisation packages in Odoo are specific to the version of Odoo you are using, so the package for Odoo v16 may not be compatible with Odoo v15. Therefore, if you are using Odoo v15 and there is no Kenya localisation package available for that version, you may need to consider upgrading to Odoo v16 or a later version that has the Kenya localisation package.

Regarding compatibility, Odoo will generally alert you if you are trying to install an app or module that is not compatible with your version of Odoo. However, it's always a good idea to check the compatibility of any app or module before installing it to avoid any potential issues.

If you do decide to upgrade to Odoo v16, it's important to note that the upgrade process can be complex and may require some technical expertise. It's recommended to back up your data and test the upgrade on a staging environment before implementing it on your live system.