FreeType, a FOSS project developing a font rendering engine, cheers on its webpage the expiration of three Apple patents related to the rendering of TrueType fonts.
While those patents were valid, the project disabled one technical component called the "bytecode interpreter" and called on its users not to use it even though the program code was in place. Now that functionality is enabled by default. Yesterday FreeType just released its latest version, 2.4.1.
Two of the three Apple patents in question were filed for in May 1989. The third one was applied for in 1992, and I presume Apple decided not to renew it because there wasn't much (if any) commercial value left after the other two TrueType patents were past the end of the 20-year maximum term of validity of US software patents.
[Update] Through Slashdot I became aware of a juxtaposition of two screenshots that shows what difference in quality the "bytecode" algorithm makes. It's pretty visible. [/Update]
It was interesting to read this because two days ago I commented on Richard Stallman's concerns over patents that could affect Mono and DotGNU and in that context I said that if RMS wants a totally patent-unencumbered development platform, it will have to be more than 20 years old. Plus it would have had to be open-sourced back then because without publication something cannot serve as prior art (meaning as a previous invention in order to invalidate patents filed later). Even the slightest change to a code base during that time span could result in some new patent infringement. But the part that's more than 20 years old is (provided that it was published back then) safe.
The FreeType example shows that sometimes useful things do become available for free thanks to patent expiration. That doesn't solve all problems, but every useful thing is potentially good news for someone. In this case, for the FreeType folks, who probably had been awaiting that moment for many years.
Several years ago, the nastiest patent related to the Graphics Interchange Format (GIF) also expired. Unisys had acted pretty much like a patent troll because its core business was in bad shape and the GIF patent became a key asset to the once-great company.
That GIF patent is the only important software patent expiration I had been aware of before reading about TrueType.
In political debates over whether or not software should be patentable, I criticized the 20-year term as being way too long for software. In a speech I gave at a demonstration against software patents in Munich in April 2004, I said that the patents reaching the end of the 20 years at that time were basically from the heyday of the Commodore 64. That was about right, although the IBM PC was already a few years old in 1984, and the Commodore Amiga was launched a year later. The TrueType stuff is now at least from the era of the breakthrough of Windows.
It will be interesting to see which FOSS projects will benefit from the expiration of the next relevant software patents.
If you'd like to be updated on patent issues affecting free software and open source, please subscribe to my RSS feed (in the right-hand column) and/or follow me on Twitter @FOSSpatents.