A new documentation is available for Squash TM 2.0 and later versions, check it here
From Squash TM 1.13 and onwards, the embedded web server with Squash TM is Tomcat (in lieu of Jetty).
The Squash directory has been modified as follows :
Squash plug-ins are now to be installed in the 'plugins' folder, formerly 'bundles' (see 2.07 - Install and configure a Squash TM plug-in)
Squash configuration are now available in the ‘squashtm.cfg.properties’ file (previously several files in the 'conf/services' folder)
The Squash upgrade procedure has been modified (see 2.06 - Upgrade Squash TM)
Squash can now be deployed in an existing Tomcat 8 server (see 2.08-Deploy Squash TM in Tomcat)