Pyomo 6.10.0

Highlights of the 6.10 release series

• Removed support for Python 3.9
• Removed hard dependency on ply
• New Model Observer package
• New solver interfaces:
  • gams_v2 solver, writer, and solution loader
  • cuopt direct solver interface
  • v2: Ongoing solver interface refactor
• ...and of course numerous minor bug fixes and performance enhancements

Changes in this release

• General
  • Remove support for Python 3.9 (#3760)
  • Typo corrections (#3779, #3831)
  • Remove external ply dependency (#3840)
  • Apply 2026 black formatting updates (#3820)
  • Update copyright to 2026 (#3846)
  • Improvements to Config classes, tests, and docs (#3790)
  • Improve efficiency of nested StreamIndenter objects (#3813)
• Core
  • Remove sorting from tabular_writer (#3804)
  • Enhance static typing (#3803)
  • Update SuffixFinder to look in context for external data objects (#3844)
• Documentation
  • Add support for Sphinx 9.1 (#3815, #3818)
  • Add formal documentation for future pyomo.contrib changes (#3768)
  • Fix docstrings in core.lp_dual transformation (#3842)
  • Update related packages page (#3849, #3853)
• GDP
  • Fix bug transforming Blocks in gdp.mbigm transformation (#3811)
• Solver Interfaces
  • Update ipopt_v2 interface (#3792)
  • Add cuOpt direct solver (#3620)
  • Improvements for KNITRO interface (#3762, #3765, #3766, #3802, #3824,
    #3826, #3827, #3837, #3794)
  • Remove iteration_count as a default Results object value (#3767)
  • Compute wall_time using time.perf_counter (#3825)
  • Incorporate Model observer into gurobi_v2 interface (#3698)
  • Add new GAMS interface, writer, and solution loader (#3683)
• Testing
  • Testing infrastructure cleanup/rework (#3764, #3770, #3773, #3810)
  • Correct broken URLs (#3761, #3796, #3845, #3847, #3848)
  • Pytest version workarounds (#3780, #3784)
  • Specify openmpi build type in testing environment (#3797)
  • Add flexibility to error checking for gurobi_minlp (#3822)
  • Update solver tests for gurobiasl 13.0.0 (#3850)
  • Rework conftest.py to support solver/writer marker expressions (#3854)
  • Relax mumps reallocation test (#3857)
• Contributed Packages
  • DoE: Disable unreliable test (#3776)
  • DoE: Correct A optimality (#3803)
  • DoE: Replace computationally expensive example with Rooney Biegler (#3828)
  • GDPopt: Improvements to LDSDA (#3830)
  • observer: Add in Model observer package (#3695, #3829)
  • Parmest: Consolidate Rooney Biegler (#3793)
  • Parmest: Update documentation (#3791)
  • PyROS: Update tests for Python 3.14 (#3782)
  • PyROS: Fix IntersectionSet implementation (#3786)
  • PyROS: Fix scaling typo in separation objectives (#3817)