Since 2018, Microsoft has been a sponsor of the [[AdoptOpenJDK]] project. It is a drop-in replacement for [[Oracle Corporation|Oracle]]'s [[Java (programming language)|Java]]/[[Java Development Kit|JDK]].<ref name="ZDNet_2020-06-24">{{Cite web|last=Foley|first=Mary Jo|date=2020-06-24|title=Microsoft completes phase one of porting OpenJDK for Windows 10 on ARM devices|url=https://www.zdnet.com/article/microsoft-completes-phase-one-of-porting-openjdk-for-windows-10-on-arm-devices/|access-date=2021-04-13|website=ZDNet|language=en-US}}</ref>
In April 2018, Microsoft released the Windows 3.0x/Windows NT [[File Manager (Windows)|File Manager]] source code licensed under the [[MIT License]].<ref>{{cite web |url=https://techcrunch.com/2018/04/09/90s-kids-rejoice-microsoft-releases-the-original-windows-3-0-file-manager-source-code/ |title=90s kids rejoice! Microsoft releases the original Windows 3.0 File Manager source code |author=John Biggs |publisher=[[TechCrunch]] |access-date=15 April 2018}}</ref><ref>{{cite web |url=https://www.theverge.com/2018/4/9/17214586/microsoft-windows-file-manager-windows-10-app-download |title=Microsoft open-sources original File Manager from the '90s so it can run on Windows 10 - The Verge |author=Tom Warren |publisher=The Verge |access-date=7 April 2018}}</ref> In August 2018, Microsoft added support for the open source [[Python (programming language)|Python]] programming language to [[Power BI]].<ref>{{Cite web|url=https://www.infoworld.com/article/3299704/microsoft-adds-python-support-to-power-bi.html|title=Microsoft adds Python support to Power BI|first=Serdar|last=Yegulalp|date=August 22, 2018|website=InfoWorld}}</ref> In October 2018, Microsoft joined the [[Open Invention Network]]<ref>{{Cite web |last1=Vaughan-Nichols |first1=Steven J. |title=Microsoft open-sources its patent portfolio |work=[[ZDNet]] |date=2018-10-10 |url=https://www.zdnet.com/article/microsoft-open-sources-its-entire-patent-portfolio/ |language=en |access-date=2019-04-21 |df=mdy-all}}</ref> and cross-licensed 60,000 patents with the open source community.<ref>{{Cite web|url=https://www.zdnet.com/article/what-does-microsoft-joining-the-open-invention-network-mean-for-you/|title=What does Microsoft joining the Open Invention Network mean for you?|first=Steven J.|last=Vaughan-Nichols|website=ZDNet}}</ref><ref>{{Cite web |last1=Gartenberg |first1=Chaim |title=Microsoft makes its 60,000 patents open source to help Linux |work=[[The Verge]] |date=2018-10-10 |url=https://www.theverge.com/2018/10/10/17959978/microsoft-makes-its-60000-patents-open-source-to-help-linux |access-date=2019-04-21 |df=mdy-all}}</ref>
In 2019, Microsoft's Windows Subsystem for Linux 2 transitioned from an emulated Linux kernel to a full Linux kernel within a [[virtual machine]], improving processor performance manifold. In-keeping with the GPL open source license, Microsoft will submit its kernel improvements for accommodation into the master, public release.<ref>{{Cite web |last1=Bright |first1=Peter |title=Windows 10 will soon ship with a full, open source, GPLed Linux kernel |work=[[Ars Technica]] |date=2019-05-06 |url=https://arstechnica.com/gadgets/2019/05/windows-10-will-soon-ship-with-a-full-open-source-gpled-linux-kernel/ |access-date=2019-05-07 |df=mdy-all }}</ref>
