Xpress Update 8.4.6

Document created by Michael.Perr on Feb 26, 2018
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Xpress Update 8.4.6 is now available on Box.com for Windows, Linux and Mac, from




This is the latest update for the Xpress 8.4 release branch. Please note that it must be installed over a prior installation of FICO Xpress 8.4 and requires a valid Xpress 8.4 license.


Release Notes:


Xpress Optimizer 32.01.09:


  • Fixed an issue in the dot product implementation of the Python interface.
  • Fixed handling of range constraints in the Python interface.
  • Fixed an internal issue related to XPRSloadlpsol.
  • Fixed an issue related to XPRScrossoverlpsol.
  • New string attribute 'XPRS_XPRESSVERSION' indicating the Xpress version ("8.4.6" for this patch)
  • Fixed a problem related to XPRS_CALLBACKFROMMASTERTHREAD when XPRS_THREADS is set to 1 and XPRS_MIPTHREADS is set to a positive number.
  • Fixed an issue that could cause the time limit for positive values of MAXTIME to be ignored in multi-threaded MIP solves.
  • Fixed an issue that prevented user solutions from being processed when HEURSTRATEGY=1.
  • Fixed an issue with presolve probing for MIPs that could result in a crash.
  • Shifting of integer variables during presolve will now be disabled when bit 10 of PRESOLVEOPS is set.


Xpress Workbench 2.1.6:


  • Fixed error when opening projects stored on a drive other than C:
  • Fixed issue where Mosel output contains unexpected symbols on Windows 7
  • Fixed another issue where Mosel appears to hang and display no output when running a model


Xpress Licensing 2.9.2:


  • Fixed a bug triggered by network adapter prefixes of 15 characters or longer.