Some information about HA Proxy software versions follows....

• version 3.1 : troubleshooting, improved config reliability, improved QUIC and H2 performance, new SPOE engine, finer error reporting
• version 3.0 : crt-stores, persistent stats, syslog load balancing, JSON&CBOR log encoding, virtual maps &acls, zero-copy from the cache, H2/H3 protocol-level protections
• version 2.9 : reverse-http, log backends, zero-copy forwarding, memory usage reduction, increased bandwidth, better general scalability, AWS-LC support, QUIC openssl compat layer, PROXY protocol manipulation`
• version 2.8 : QUIC now prod ready, Lua-based mailers, OCSP auto updates, LetsEncrypt, wolfSSL support, RFC7239 "forwarded", listeners on more than 64 threads, perf/usability/reliability/observability improvements
• version 2.7: Traffic shaping, QUIC improvements, thread groups, easier switch to alternate SSL libraries, improved debugging
• version 2.6: QUIC/HTTP3, OpenSSL 3.0, better usability, improved code accessibility and maintenance
• version 2.5: runtime server addition/removal, runtime CA/CRL updates, native HTTP client, simplified HTTPS logging, default TCP/HTTP rulesets, JWT validation, and more
• version 2.4: syslog and DNS over TCP, multi-threaded Lua, full sharing of idle conns, lower latency, server-side dynamic SSL update, Opentracing, WebSocket over H2, atomic maps, Vary support, new debugging tools, even more user-friendly CLI and configuration, lots of cleanups
• version 2.3: syslog forwarding, better idle conn management, improved balancing with large queues, simplified SSL managment, more stats metrics, stricter config checking by default, general performance improvements
• version 2.2: runtime certificate additions, improved idle connection management, logging over TCP, HTTP "return" directive, errorfile templates, TLSv1.2 by default, extensible health-checks
• version 2.1: improved I/Os and multi-threading, FastCGI, runtime certificate updates, HTX-only, improved debugging, removal of obsolete keywords
• version 2.0: gRPC, layer 7 retries, process manager, SSL peers, log load balancing/sampling, end-to-end TCP fast-open, automatic settings (maxconn, threads, HTTP reuse, pools), ...
• version 1.9: improved multi-threading, end-to-end HTTP/2, connection pools, queue priority control, stdout logging, ...
• version 1.8: multi-threading, HTTP/2, cache, on-the fly server addition/removal, seamless reloads, DNS SRV, hardware SSL engines, ...
• version 1.7: added server hot reconfiguration, content processing agents, multi-type certs, ...