Apache OpenOffice (AOO) is an open-source office productivity software suite.

[8] Apache OpenOffice is developed for Linux, macOS and Windows, with ports to other operating systems.

[9] Difficulties maintaining a sufficient number of contributors to keep the project viable have persisted for several years.

[32] Its reasons for doing so were not disclosed; some speculate that it was due to the loss of mindshare with much of the community moving to LibreOffice[33] while others suggest it was a commercial decision.

[63] Notable claimed improvements in file format handling in 4.0 include improved interoperability with Microsoft's 2007 format Office Open XML (DOCX, XLSX, PPTX)[64] — although it cannot write OOXML, only read it to some degree.

Apache OpenOffice 4.1.0 was released for x86 and X86-64 versions of Microsoft Windows XP or later, Linux (32-bit and 64-bit), and Mac OS X 10.4 "Tiger" or later.

[54] In January 2015, the project reported that it was struggling to attract new volunteers because of a lack of mentoring and was badly in need of contributions from experienced developers.

[11] Red Hat developer Christian Schaller sent an open letter to the Apache Software Foundation in August 2015 asking them to direct Apache OpenOffice users towards LibreOffice "for the sake of open source and free software",[73] which was widely covered[74][75][76][77][78] and echoed[79][80][81][82] by others.

Brett Porter, then Apache Software Foundation chairman, asked if the project should "discourage downloads".

[84] The Register published an article in October 2018 entitled "Apache OpenOffice, the Schrodinger's app: No one knows if it's dead or alive, no one really wants to look inside", which found there were 141 code committers at the time of publication, compared to 140 in 2014; this was a change from the sustained growth experienced prior to 2014.

The article concluded: "Reports of AOO's death appear to have been greatly exaggerated; the project just looks that way because it's moving slowly.

[87] During this period, in April 2015, a known remote code execution security vulnerability in Apache OpenOffice 4.1.1 was announced (CVE-2015-1774), but the project did not have the developers available to release the software fix.

[89] It was revealed in October 2016 that 4.1.2 had been distributed with a known security hole (CVE-2016-1513) for nearly a year as the project had not had the development resources to fix it.

[90] 4.1.3 was known to have security issues[91] since at least January 2017, but fixes to them were delayed by an absent release manager for 4.1.4.

[93] Further unfixed problems showed up in February 2019, with The Register unable to get a response from the developers, although the existing proof-of-concept exploit doesn't work with OpenOffice out-of-the-box.

[14] Version 4.1.11 was released in October 2021 with a fix for a remote code execution security vulnerability (CVE-2021-33035) that was publicly revealed the previous month.

[96] In October 2024, the Apache Software Foundation reported further problems, describing OpenOffice's security health status as "amber", with "three issues in OpenOffice over 365 days old and a number of other open issues not fully triaged.

Various features lined up for 4.1 include comments on text ranges, IAccessible2, in-place editing of input fields, interactive cropping, importing pictures from files and other improvements.

LibreOffice earlier rebased its LGPL-3.0-or-later codebase on the Apache OpenOffice 3.4 source code (though it used MPL-2.0, not the Apache-2.0) to allow wider (but still copyleft) licensing under MPL-2.0 and LGPL-3.0-or-later.