General Differences
As the version upgrades, the new versions support extra compression techniques to increase the network speed.
HTTP/1.1
The most base HTTP version.
HTTP/2
This blog explains well in detail.
Date: Since 2015
Speed improvements through:
- Request multiplexing: Multiple requests for data in parallel over a single TCP connection
- Header compression.
- Binary protocol
HTTP/3
This blog explains well in detail.
Also check Android Official Documentation.
Date: Since 2019
QUIC is a network layer protocol implemented over UDP. Simply put, QUIC is an improvement over TCP. On top of TCP, QUIC also provides:
- Dramatically reduced connection establishment time
- Improved congestion control
- Multiplexing without head of line blocking
- Forward error correction
- Connection migration
