On HTTP/2, Google says [1]:

> all existing applications can be delivered without modification....

> The only observable differences will be improved performance and availability of new capabilities...

Lucidcharts may have an inadequate backend, but it wasn't a problem until they moved to HTTP/2, so those statements weren't true for them. For anyone else rolling out HTTP/2, that is worth bearing in mind.

[1]: https://developers.google.com/web/fundamentals/performance/h...