Revise Online Availability Calendar to Replace dateroutine.pm

I need a revision to my existing online availability calendar application, which is written in .cgi and uses HTML templates. The current functionality relies on dateroutine.pm, which is no longer supported by my host. The goal is to restore full functionality by replacing dateroutine.pm with an alternative solution. I will provide all existing files for the application, and the freelancer will deliver all revised files. The project must be completed within two weeks.