These are the highlights of new features or additions to existing features in v5.0.x and 5.1.x. For the complete list of all changes see this JIRA Release Notes.

General changes

• We do no longer require the Boost library to build!

Jira: TS-3068, 

New configuration options

• You can now force unsatisfiable Range: requests to go to origin even when read-while-writer is in effect. This can help avoid significant latency on large objects. The setting is overloaded on the existing proxy.config.cache.enable_read_while_writer configuration.
• The option to specify configuration location, proxy.config.config_dir, is now actually implemented.
• Add option to support SO_LINGER to origin server, via proxy.config.net.sock_option_flag_out.

Jira: TS-2314, TS-3192, TS-3119

TLS

 We continue to improve our TLS (HTTPS) features and support. Noteworthy in 5.2.x is:

• SSLv3 is now disabled by default!
• Dynamic TLS record size tuning. According to Ilya, this makes us the first server that is all Green. 
• Add forward secrecy support with DHE.
• Add Add ssl_pre_handshake hook  hook for better plugin access to SSL handling.
• Improved session cache, for better performance and scalability.
• New configuration for OpenSSL session cache, proxy.config.ssl.session_cache.auto_clear.

Jira: TS-3153, TS-2503, TS-2417, TS-2956, TS-3080, TS-3127

Minor Changes

traffic_line

• traffic_line -m is now using an unachored regular expression, similar to how diagnostic tracers work.
• traffic_line --backtrace will produce a stack backtrace for all running threads.

Jira: TS-3034, TS-3145

traffic_layout

A new command line utility, traffic_layout, is now available. This will show the layout and configuration option for the ATS build tree.

Jira: TS-3041

traffic_via

This is a new command line tool, to parse and decipher the Via: header that Traffic Server can produce. This is useful for debugging e.g. cache results etc.

Jira: TS-3149

traffic_crashlog

This is the helper application around the new crash logging feature. For more information, see the documentation.

Jira: TS-3195

Plugin Improvements

The following plugins have new features and improvements.

header_rewrite

• We now support variable expansion in the set-redirect operator.
• You can now do matching operators on the port.
• We do not need Boost.

Jira: TS-2955, TS-3108, TS-3068

stats_over_http

This plugin will now emit JSON numbers.

Jira: TS-3071

background_fetch

• The plugin behavior and activation can now be controlled per remap-rule.
• You an control the behavior based on content type.

Jira: TS-2682, TS-2683

Plugin APIs

The following additions were made to the plugin APIs:

• TSMutexDestroy() was added, for symmetry with the TSMutexCreate() API.
• TSTextLogObjectRollingSizeMbSet() was added, it as simply missing.
• TSHttpHdrHostGet() was added.

Jira: TS-1432, TS-3059, TS-3101

 Developer Changes