I am developing a module for Stripe that uses the Elements Stripe.js version that would require less PCI requirements and support of other Stripe payment features.  The WHMCS stripe module uses Stripe.js v2 which requires more PCI requirements and it is deprecated.  Stripe uses "off site tokenization" by using their own forms.   There is a request to switch to Elements but has been there for a year and not ETAs as well as only supporting cards and not other stripe payment options (beyond apple p