Libraries and Version Controllers

You could always use Webhooks in GitHub, if you're using that, to update a URL and have it pull a new version down.

You could also create a git hook on push and shoot the changes (or even just a notice) to your other sites.

Other than that, I don't know of a way to make it happen automatically.

If you package things up as a Composer-loadable library, instead of a strictly CI one, you could simply do a composer update on each project when you work on it again. You could even use Composer and CodeIgniter Installers to pull your package down and throw the library in your libraries, or third-party folder for you. That's possibly the best solution, in my opinion.

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