integrated audio and video player allows playing media from files stored in OnlyOffice. The Projects module is developed for managing project stages: planning, team management and task delegation, monitoring and reporting. This module also includes Gantt charts for illustrating the projects stages and dependencies between tasks. The CRM module allows maintaining client databases, transactions and potential sales, tasks, client relationship history. This module also provides online billing and sales reports. The Mail module combines a mail server for creating own-domain mailboxes and mail aggregator for centralized management of multiple mailboxes. The Calendar module allows planning and monitoring of personal and corporate events, task deadlines in Projects and CRM, sending and receiving invitations to events. The Community module offers corporate social network features: polls, corporate blog and forums, news, orders and announcements, and a messenger. Technology It is technologically based on three components: Document Server, Community Server and Mail Server. The Document server maintains text document, spreadsheet and presentation editors and is written in JavaScript using HTML5 Canvas element. The Community server hosts all functional modules of OnlyOffice. It is written in ASP.NET for Windows and in Mono for Linux and distributions. The Mail server represents set of components that allows creating corporate mailbox using default or custom domain names. Mail Server is based on the iRedMail package which consists of Postfix, Dovecot, SpamAssassin, ClamAV, OpenDKIM, Fail2ban. Desktop and mobile apps OnlyOffice Desktop is an offline version of OnlyOffice editing suite. The desktop application supports collaborative editing features when connected to the portal, Nextcloud, ownCloud, kDrive, Seafile, or Liferay. It is offered free of charge for both personal and commercial usage. The desktop editors are cross-platform available for Windows XP or later (x32 and x64), Debian, Ubuntu and other Linux distributions based on RPM, Mac OS 10.10 and newer, including computers built on Apple Silicon. Besides platform-specific versions there is also a portable option. OnlyOffice Desktop Editors are available for installation as Flatpak, snap and AppImage packages on Linux. Editors are compatible with MS Office (OOXML) and OpenDocument (ODF) formats and support DOC, DOCX, ODT, RTF, TXT, PDF, HTML, EPUB, XPS, DjVu, XLS, XLSX, ODS, CSV, PPT, PPTX, ODP, DOTX, XLTX, POTX, OTT, OTS, OTP, and PDF-A. Like the online editing suite, the basic toolset of OnlyOffice Desktop can be upgraded using side plugins. The desktop editors are distributed under AGPL-3.0-only license for personal and commercial usage. OnlyOffice editors are also