The board made the announcement overnight on the Ubuntu development announce and discussion mailing lists.
It comes a few days after iTWire ran two stories, one about the possible inclusion of more Mono-dependent applications in the next release and the second about a board meeting held in March which saw "no significant cause for concern over its (Mono's) IP situation."
Mono is a project to develop an open source implementation of Microsoft's .NET development environment initiated some years ago by current Novell vice-president and GNOME co-founder Miguel de Icaza.
Scott James Remnant, senior software engineer at Canonical, the parent company of Ubuntu, said in the announcement that the board had not received any claims of infringement against the Mono stack, and was not aware of any such claims having been received by other similar projects.
"It is common practice in the software industry to register patents as protection against litigation, rather than as an intent to litigate. Thus mere existence of a patent, without a claim of infringement, is not sufficient reason to warrant exclusion from the Ubuntu Project," he wrote.
Hence, the statement concluded, "the Ubuntu Technical Board sees no reason to exclude Mono or applications based upon it from the archive, or from the default installation set."
The Software Freedom Law Centre, which provides "legal representation and other law-related services to protect and advance Free, Libre and Open Source Software" has a diametrically different view.
Following the statement made by Free Software Foundation chief Richard M. Stallman against Debian's inclusion of Mono as a default, SFLC technology director, Bradley Kuhn , has written an essay, backing Stallman's view about it being better to avoid a language like C#.
Kuhn pointed out that programming languages and their associated standard libraries and implementations evolved in three basic ways:
a free software community designed and implemented a language in a grassroots fashion (Perl, PHP, and Python);
a single corporate entity controlled a language and its canonical implementation, even convincing some standards body to adopt it, but usually retaining complete control (C# and Java); and
a single corporate entity controlled the language initially, but more than 20 years had passed and the language now had many proprietary and free software implementations (C and C++)
"We have to assume that the USPTO (American patent office) has granted many patents that read on any software a person can conceivably write. The question is always: of all the things you can write, which has the most risk of patent attack from the patent holders in question?" Kuhn wrote.
He argued that if a single entity controlled a language, there was always a higher risk of patent attack by the same entity or patent trolls. In the case of community-designed languages, the risk was spread over many companies and other entities, hence the chance of an attack was much less.