If you are using AIM plugin and the orders are going through then you have no real concern. As long as the correct updates are happening on your end. To use sha512 you need to generate a signature key. This is a separate credential from your login and Transkey that you likely haven’t used until now. If and when you have the most up to date version of the plugin, you want to paste that signature key into the plugin.
With AIM you do not need sha512 or md5 to submit transactions. The main function for you is to aid in validating transaction responses. Usually what happens is based on the transaction response updates are made on your records. If your records are getting updated even when sha512 fails then it’s of no consequence. The above, however, will get rid of that message.