Google will crawl sites over HTTP2 from November 2020
From mid-November 2020, Google will start crawling websites over HTTP2. Sites that support the HTTP/2 protocol will see improvements in crawl quality, but not in crawl speed, Google notes.
Not all sites will be crawl over h2 protocol, but only those that support it, and which will show the loading efficiency. That is, the search engine will compare how much it will save resources by loading a specific site via HTTP2, and if there are no such savings, it will continue to use HTTP/1.1. The main metric is the number of requests per second (qps).
Despite the fact that Google does not promise changes in terms of indexing or crawling the site when switching to the new technology, nevertheless, when resources are released, the search engine will be able to direct them to crawl most of the site. I believe that there will be some small benefits for the owners of HTTP2 sites."
In November, HTTP2 crawling will target a small number of sites. Depending on the success of the project, the search engine will roll it out to more resources. No additional action is required by the site owners. Everything will happen automatically. But you can check if your site supports HTTP2 by following the link.
Interestingly, in 2017, Google, represented by John Mueller, noted that the search engine does not see the benefits of HTTP/2 for itself.
HTTP/2 is a new data transfer protocol introduced to the public in 2014 and approved in 2015. Compared to HTTP1.1, it has one noticeable advantage - it does not create a separate connection for downloading each file, but downloads all of them in parallel, in one stream. Thanks to this, there is no need to create CSS sprites, minify jаvascript, and transfer images to other domains.
Source: Google Blog