4.0.0-rc1 (2026-05-14)

What's Changed

• Add styles to theme for prompt-toolkit completion styles by @tleonhardt in #1653
• Removed feedback_to_output settable and made pfeedback() consistent by @bambu in #1647
• Refactor internal naming to _cmd_app and remove legacy parseline() method by @kmvanbrunt in #1659
• Added LRU caching of converted prompt-toolkit styles and colors. by @kmvanbrunt in #1657
• Added monkey patch to handle argparse deepcopy issue introduced in Python 3.15.0b1. by @kmvanbrunt in #1662
• Added prompt-toolkit version of the app theme which remains synchronized when theme is updated. by @kmvanbrunt in #1661
• Added ability to incrementally update the theme. by @kmvanbrunt in #1664
• Expanded subcommand management API. by @kmvanbrunt in #1663
• Made traceback_width a Settable.
• Drop support for Python 3.10 by @tleonhardt in #1665

Full Changelog: 4.0.0-b6...4.0.0-rc1