The GitHub Copilot app now supports stacked sessions and stacked pull requests, which allow a series of tasks in the same repository to build on each other. This feature proved transformative for a developer modernizing a personal app originally built in 2014 with outdated dependencies like React 15, Less, and an old version of react-bootstrap.
Initial Attempt and Plan
The developer first tried a one-shot prompt in Plan mode, asking Copilot to modernize the frontend, remove Less, improve accessibility and responsiveness, and decide between Tailwind and vanilla CSS. They used Claude Opus 4.8 and GPT-5.5 for reviews, but the initial attempt failed due to an overlooked dev branch that contained partial modernizations.
Switching Sessions and Handling Compatibility
Realizing the dev branch had unmerged changes, the developer asked Copilot to create a new session, close the attempted pull request, and port styling decisions to the dev branch. Copilot handled this smoothly, saving time and frustration.
Addressing Legacy Warnings
During testing, old warnings from react-bootstrap (like findDOMNode and componentWillReceiveProps) appeared. The developer used Plan mode again to decide whether to upgrade or replace the library. Copilot recommended replacing it entirely.
Stacking Sessions and Pull Requests
To avoid scope creep, the developer prompted Copilot to create a pull request for existing work and then start a new session for the react-bootstrap replacement, branching off the existing work. Copilot automatically created a stacked session and a stacked pull request, forming an ordered chain that targets the branch of the pull request below it.
Outcome
The stacked sessions and pull requests made the modernization process much easier, allowing the developer to ship changes incrementally. The feature is now available in the GitHub Copilot app, and pull request stacks can be used anywhere you commit code on GitHub.
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