Yes multiple headers shouldn’t be a problem.
The plugin will contain HMAC blueprints for MD5, SHA1, SHA256 and SHA512.
You could either send the money as a donation to [EMAIL=“paypal@.com”]paypal@.com, or I can send you an invoice to be paid as a bank transfer (IBAN).
The HMAC code will be done within a couple days, releasing the plugin update to the marketplace can take up to a week (depends on how fast Epic is).
If you use the source code version of the LE Extended Standard Library you won’t have to wait for Epic to release the plugin update to the marketplace.