The latest stable release of Apache Traffic Server is 4.2.1, released on 2014-04-29. New in the 4.x releases is that we now follow the Semantic Versioning scheme. The goal is to release minor versions quarterly, and within the major version these are all compatible.

When downloading from a mirror, please be sure to verify the checksums and OpenPGP compatible signature. You can also browse through all releases and checksum signatures.

Current v5.x Release -- 5.0.0

Apache Traffic Server 5.0.0 was released on June 17, 2014. [PGP] [MD5] [SHA1]

Traffic Server 5.0.0

This is the next major release and includes API changes and experimental SPDY support

More details are also in the CHANGES log and the the Jira Release Notes

Current v4.x Release (Long Term Support) -- 4.2.1

Apache Traffic Server 4.2.1 was released on April 29, 2014. [PGP] [MD5] [SHA1]

Traffic Server 4.2.1

This is primarily bug fix release since 4.1.2, but there is also a host of new features and minor improvements or cleanups on the code-base.

Upgrading from v3.2 to v4.x implies reinitializing the cache, so existing cache data will be erased. This should happen automatically on startup, but please be careful. For details on upgrading to v4.x, see these instructions.

More details are also in the CHANGES log and the the Jira Release Notes

Legacy v3.2.x Release (Long Term Support) -- 3.2.5

Apache Traffic Server 3.2.5 was released on July 31, 2013. [PGP] [MD5] [SHA1]

Traffic Server 3.2.5

This is a maintenance release, with a small highlight on SSL fixes.

If you are upgrading from the previous stable releases (v3.0.x), please see these instructions.


  • [TS-1470] - 3.2.x - Large cache (> 16TB) not working?
  • [TS-1483] - Traffic Manager when autoconf fd > 32 will cause endless spins causing traffic_cop to kill server -- Backport 3.2.x
  • [TS-1779] - Crash using ssl_ca_name
  • [TS-1784] - 3.2.x - FreeBSD disk calculations are wrong
  • [TS-1785] - 3.2.x - ATS 3.2 does not build with gcc 4.8 anymore
  • [TS-1900] - Building ATS 3.2.4 on Ubuntu 10.04.4 LTS fails on make due to hwloc.
  • [TS-1903] - 3.2.x - Remove use of JEMALLOC_P
  • [TS-1905] - TS hangs (dead lock) on HTTPS POST/PROPFIND requests
  • [TS-1918] - 3.2.x - SSL hangs after origin handshake
  • [TS-1923] - 3.2.x - Fix resolve_logfield_string()


  • [TS-1902] - 3.2.x - remove libiconv dependency

Archived Releases

Apache Traffic Server Archive

Note: Upgrading from v2.0.x or v2.1.8 and earlier requires that you migrate to the new records.config configuration file. You should also clear all caches after upgrading (e.g. sudo traffic_server -Cclear), as well as deleting the hostdb files (var/trafficserver/host.db and etc/trafficserver/internal/hostdb.config).