I am using magento v2.2.6. I am getting notification regarding the new patch release by magento for authorize.net payment method. But i am not using authorize.net payment method in my magento setup. Is still I need to apply that patch or I can skip it?
Earlier Authorize.net using MD5 as a encryption algorithm. Now they are upgrading and going with Signature Key (SHA-512) encryption.
As, all existing Magento using earlier encryption, So all Magento need to Patch (Replace some files) to correctly working of Authorize.net as a payment method.
If you not using Authorize.net as payment method (also planning not to be use in future): Don't do anything just ignore this message
If you are using it, you need to apply patch as per official given in the documentation.