These cumulative updates to Visual Studio 2015 include a variety of bug fixes and capability improvements.

If you have Visual Studio Community 2015 installed on a machine with Internet access, Update 1 displays in the Notifications Hub. To install, select the Update 1 notification, and then complete the installation actions. You can also download Update 1 here.

Visual Studio Community 2015 with Update 1 is a free, fully featured, and extensible IDE for individual developers, open source projects, academic research, education, and small professional teams. Create applications for Windows, Android, and iOS as well as web applications and cloud services. Build apps for any platform. Use designers, editors, debuggers, and profilers in a single tool. Access thousands of extensions and more.

Note: If you have installed Visual Studio Community 2015 (original release version) and run this download from this page, only Update 1 is installed. If you haven't installed Visual Studio Community 2015 and run the download, both Visual Studio Community 2015 and Update 1 are installed. In either instance, Visual Studio 2015 Language Packs (original release versions) can also be installed.

VS Release Notes
TFS Release Notes
VS Known Issues
System Requirements
Compatibility