we are about to release the next Toolbox release (1.5.0). While we are finishing up the change log , we would like to ask the community to test the release candidate  (unless show stoppers are found, the release candidate will eventually just be renamed).
Almost 500 new commits make up the 1.5.0 since the last release in early 2014 (see commit 6639bd91f4bb4f2233c05720ecea18
14686d6739). An incomplete high-level list of changes is:
* Distributed TLC in the Cloud (preview, lacks final documentation) 
* Portable specs (only store relative path names)
* Persistently store customized sash ratio in TLC Errors view
* Flip sort order in TLC Errors view. Sort variables alphabetically
* Make better use of screen estate on large displays
* Improved scalability and performance (order of magnitude) with TLC Liveness checking (milestone 1)
* Minor enhancements (see commit log)
* Liveness checking produces invalid counter-example 
* Negative seek offset Exception with Liveness checking 
* Liveness checking in simulation mode is buggy 
* Fixed several startup crashes and hangs
* Fixed race conditions when launching TLC , and in TLC Errors view
* Drop Toolbox compatibility with Java < 1.7
* Better compatibility with recent Mac and Linux (switched to Eclipse foundation 4.4)
* Much improved test coverage
* Can switch to experimental liveness checking implementation in simulation mode (-Dtlc2.tool.Simulator.
* Report statistics about behavior graph properties (-Dtlc2.tool.liveness.
* Significantly extended code comments
* Sign distributed TLC workers to remove startup warning
Please report bugs by responding to this message or by opening issues at Codeplex .
tlatoolbox/staged/products/or https://bugzilla.tlaplus.net/ tlatoolbox/staged/products/
SourceControl/changeset/ 6639bd91f4bb4f2233c05720ecea18 14686d6739