Migration from PHPExcel
PhpSpreadsheet introduced many breaking changes by introducing namespaces and renaming some classes. To help you migrate existing project, a tool was written to replace all references to PHPExcel classes to their new names. But there are also manual changes that need to be done.
RectorPHP can be used to migrate
automatically your codebase. Assuming your files to be migrated lives
src/, you can run the migration like so:
composer require rector/rector --dev vendor/bin/rector process src --set phpexcel-to-phpspreadsheet composer remove rector/rector
For more details, see RectorPHP blog post.