Recently Authorize.net has made changes to their product line offerings to consolidate several offerings. This means that if you are using Authorize.net on your WooCommerce website, the plugin that you are using will be obsolete soon. WooCommerce has responded by releasing a new Authorize.net plugin which will replace the several other plugins that there used to be (AIM, CIM, DPM, and SIM). If you host with us, we will be switching you over to the new plugin so you should not experience any problems with your WooCommerce store.
You can read more about the new plugin here.