After installing when I go to the edit button, where I will be entering the bitpay details I get the following error :

Fatal error: Call to undefined method Loader::library() in /home/mydomain.com/public_html/admin/controller/payment/bitpay.php on line 25

When sending the information to the BitPay the plugin adds more information to the posData than needed. The "hash" needs to be removed and validation needs to make a call to BitPay to receive the invoice and verify against that.

Steps to Reproduce:

• Install http://premium.wpmudev.org/project/membership/ and activate and enable
• Go through and setup the the membership plugin and configure one of the membership levels to have a price attached to it
• Install this BitPay plugin and enable
• Goto the the Payment Gateways for the membership plugin and update the settings with an API key
• Open up a new (prefer incognito mode with chrome) browser and register on the site, during checkout just click the button and the error can be reproduced.

So this is forked off of ionux/, rather than the other way around, which causes some issues. For example, the readme links to the ionux branch, which is 4 commits behind the master branch, probably not the version we want people to install. I would say this can't be verified until that specific issue with the readme has been fixed.

regular membership 2 plugin does not support API integrations.
gateways in Membership 2 Pro are under different directories.
this plugin might need an update.