@dansup It looks like this library support only the old and deprecated version of the webpush specifications (like mastodon)

The official webpush RFC is out for 7 years. And it avoids a few things like parsing the headers to add in the pushed messages (for FCM/APNS/UnifiedPush) to be able to decrypt the message, which is necessary with the draft. (cf. comment from one of the RFC author [1])

With the published version, pushed message to UnifiedPush endpoint can be decrypted by the app.

You may want to consider using the published RFC before it is too late and you have to write backward compatible transition (like mastodon has to do)

[1] github.com/UnifiedPush/wishlis