OnlyOffice is a cloud office suite, which allows the users to create documents, spreadsheets and presentations and access them remote.

It has support for the most popular file formats: PDF, TXT, DOCX, DOC, ODT, RTF, HTML, EPUB, XLS, XLSX, ODS, CSV, HTML and PPTX and has good integration with Google Drive, OneDrive, Dropbox, Box, OneDrive.
The latest version available is OnlyOffice 8.5, which has been recently released, permitting the users to drag and drop folders, setup mail address, send large files as links nad got some translation updates.
Installation instructions:
The latest versions of OnlyOffice are available via repository maintained by the developers, so everybody can install and update onlyoffice easily.
To install OnlyOffice on Ubuntu, Linux Mint, Pinguy OS, Elementary OS, Deepin, Peppermint, LXLE, Linux Lite, Debian, SparkyLinux, Robolinux and other Ubuntu, Debian and derivative systems, you have
Add the repository to your system:
$ sudo sh -c 'echo "deb http://download.onlyoffice.com/repo/debian squeeze main" >> /etc/apt/sources.list'
$ wget http://download.onlyoffice.com/repo/onlyoffice.key
$ sudo apt-key add onlyoffice.key
Update the local repository index and install the onlyoffice package:
$ sudo apt-get update
$ sudo apt-get install onlyoffice
Next, set passwords for MySQL.
To access OnlyOffice, open your web browser, navigate to http://127.0.0.1 and set the username/email and password.
Optional, to remove onlyoffice, do:
$ sudo apt-get remove onlyoffice