Version 4.0.6

• Fix - A WC 2.6 backwards compat issue with function from WC 3.0.
• Fix - Subs renewal sometimes failed due to parameters being different.
• Fix - Stripe accepts only NO for Norwegian language on Stripe Checkout.
• Fix - Refund fees may not accurately reflect net fees. Props @rvola.
• Fix - Undefined SERVERNAME property in some cases.
• Fix - Potential issue when a charge parameter changes due to initial failed request causing retries to fail.
• Fix - When 3DS is not required, failed payments was not change order status to failed.
• Fix - Potential duplicate order processes on WC side when webhook and redirect has a race condition.
• Remove - Checkout validation and let WC handle it.
• Update - Stripe API version to 2018-02-06.
• Add - Webhooks for review open/closed for Radar.
• Add - Hook wc_stripe_refund_request for refund request arguments.
• Add - Hook wc_stripe_validate_modal_checkout to enable 3rd party checkout validation.
• Add - Hook wc_stripe_validate_modal_checkout_action.