The length of newly generated Shopify access tokens will increase from 32 to 38 characters, adding a static prefix of
shpat_ (for public apps),
shpca_ (for custom apps), or
shppa_ (for legacy private apps). This change will take effect on April 1st, and will impact all access tokens generated after this date.
This is a breaking change only if your application makes assumptions regarding the length of Shopify access tokens. For example, if your app store Shopify access tokens in a 32-character database field or validates that they are exactly 32 characters, then you should adjust your application or database so it can accept longer access tokens prior to April 1st. Existing access tokens will continue to function in their 32-character form until they expire or are re-requested.
Learn more about authenticating your Shopify app from the Shopify Help Center.