STIL is released under the terms of the GNU General Public License. It has been developed and tested under Sun's Java J2SE1.4.1, but is believed to run under other 1.4 or 1.5/5.0 versions of the J2SE. It is not currently source-compatible with Java 5.0 however (because of the expansion of the DOM interface to cover DOM level 3), so if you wish to compile it yourself you will need a 1.4 version of the JDK.
An attempt is made to keep backwardly-incompatible changes to the public API of this library to a minimum. However, rewrites and improvements may to lead to API-level incompatibilities in some cases, as described below. The author would be happy to advise people who have used previous versions and want help adapting their code to the current STIL release.