PhpSpreadsheet is a library written in pure PHP and offers a set of classes that allow you to read and write various spreadsheet file formats such as Excel and LibreOffice Calc.
Read more about it, including install instructions, in the official documentation. Or check out the API documentation.
Please ask your support questions on StackOverflow, or have a quick chat on Gitter.
PhpSpreadsheet is the next version of PHPExcel. It breaks compatibility to dramatically improve the code base quality (namespaces, PSR compliance, use of latest PHP language features, etc.).
Because all efforts have shifted to PhpSpreadsheet, PHPExcel will no longer be maintained. All contributions for PHPExcel, patches and new features, should target PhpSpreadsheet master branch.
Do you need to migrate? There is an automated tool for that.
PhpSpreadsheet is licensed under MIT.