I know by now you've seen the notice by the guy claiming to "revoke" the GPL license on his code, because I'm getting email about it.
Here's the answer to your question:
No. One can't retroactively revoke licenses previously granted, unless the
license terms allow you to do so.
The most you can do is stop granting
Yes, I verified this with an attorney. Here's the GPL v2. See any terms allowing you to revoke? Me neither. You can find a lot of resources to help you understand the GPL on Groklaw's permanent GPL resources page. I'm doing my part, and I hope the guy does his by studying it.
If you change your mind and don't want to use the GPL any more, you can stop and use something else on new code going forward, and you can dual license your own code, but you can't redo the past and pull back GPL'd code. That's one of the beauties of the GPL, actually, that even if some individual gets a bug up his nose, or dies and his copyright is inherited by his wife who doesn't care about the GPL and wants to take it proprietary, or just to imagine for a moment, a Megacorp were to buy off a GPL programmer and get him to pretend to revoke the GPL with threats, and even if it were to initiate a SCO-like bogo-lawsuit (based perhaps on a theory under Copyright Law § 203, termination of rights -- lordy do we have to endure a living demo in some courtroom somewhere of every antiGPL theory found on every message board before they give up?), it doesn't matter ultimately, I don't think, as to what you can and can't do with the GPL.
The GPL is what it is. Please don't use it if you don't like the terms.
By the way, it just got a little harder to change a license in a standards context, if there is public harm.
I don't know if you read Andy Updegrove's explanation about the FTC decision in the N-Data case, but I recommend you do. The majority decision is here [PDF] and two dissents are linked in the article. It was in a standards context, regarding ethernet, where a promise to license at a certain rate was revoked by a later patent purchaser, who wanted more, one you and I would probably call a patent troll. The FTC, noting the ubiquity of the standard said it wouldn't be fair to let that happen, and it expressed concern about the harm that could arise from what it called "opportunistic lawsuits or threats arising from the incorporation of patented technologies into a standard after a commitment by the patent holder":
As a result, firms may be less likely to rely on standards, even standards that already exist. In the creation of new standards, standard-setting organizations may seek to avoid intellectual property entirely, potentially reducing the technical merit of those standards as well as their ultimate value to consumers.
It's a major step, in my view, in the right direction, because the FTC took action not because of any law-breaking but based on the harm to the public. It's been my worry about patent promises and licenses that down the road, the patents could be sold to someone new, and the new owner would take the position that it hadn't made any promises to anyone. If the promise is personal, from the corporate entity to you personally, as Microsoft's is regarding MSOOXML, would it continue to be enforceable after a sale of the patents which are covered by the patent promise? I still don't know for sure, and that is just one of the things that worries me about it. Unfortunately, nothing about that will be discussed or resolved by ECMA or at the upcoming meeting in February. It's off the table. So if that concerns a national body, all it can do is vote no. Alex Brown, who is in charge of the meeting, says the SRC would like National Bodies to write and specify what they consider the most important issues they'd like to discuss.
But I view this FTC ruling as a step in the right direction of confirming the reliability of IBM's, Nokia's, Sun's, and others' patent licenses and promises not to sue -- even in any alternate universe where some entity suddenly went bad and wanted to reverse course. But, here's the big question: would the FTC see the importance of FOSS in the same way it now sees the importance of open standards? I hope so, but that is the unknown factor in this analysis.
But seriously, can you imagine if it were possible to just change a license like the GPL any time you wanted to, without any warning that such a thing could happen? Think of the disruption to the marketplace if no one could ever rely upon a license's terms with confidence. How do you build your business on sand like that? What judge would fail to consider that level of harm to the public? There might be one somewhere. Maybe if the guy can get the Blackberry judge, but otherwise, I can't see any hope for him. If it were me, though, I'd dump his code so fast it would make a hissing noise, and I'd prefer never to use any code from him ever again, since he's not, to me, reliable as to his decisions. Who wants to be the test case, though? And besides, I prefer to use GPL code. Ask your lawyer for anything that matters.
Speaking of MSOOXML, you will greatly enjoy Rob Weir's latest, What every engineer knows. He writes about building a bridge. It's an analogy:
Along comes MegaCorp, who wants to build a bigger bridge, a much bigger bridge than any attempted previously, a MegaBridge.... Of course, the fact that MegaBridge is right down the street from the new bridge that just opened last week is a bit odd. But MegaCorp tells us that is OK. We're not required to use their bridge if we don't want to.
Further suppose MegaCorp also wants to construct this MegaBridge in record time, faster than others have constructed bridges even a fraction of their size....
But MegaCorp wants the MegaBridge to open on time. They force the inspection to continue, even though the inspectors claim there is not enough time. In order to "help" the inspection and despite the obvious conflict of interest, MegaCorp instructs a large number of its own employees, qualified or unqualified, to volunteer as bridge inspectors. They further recruit employees from subsidiaries and suppliers to become inspectors as well. In at least one case, MegaCorp tells a supplier, newly-minted as an inspector, "Don't worry if you know nothing about bridges. We'll tell you what to say. All you need to do is say that the bridge is safe. You'll be rewarded later for helping us here."...
The inspectors are polled to see whether the bridge can be certified. The vote is close, but the answer is no, the MegaBridge cannot be certified in its current condition. The inspectors, mainly the older, more experienced ones, record a report of 3,522 specific defects in the MegaBridge, far more defects than have ever been found in any other bridge.
MegaCorp is irate.... "We must open the bridge on time!" they yell. The MegaCorp engineers work day and night, over weekends, over the holidays even, in order to develop written proposals to address each of the reported flaws in the bridge. The inspectors are given the proposals and asked whether they believe the proposals are sufficient to allow the MegaBridge to be certified. Although the newly-minted inspectors are quick to affirm the adequacy of the proposal, the old-timers just shake their heads in disbelief, with one stating to the press:
"You could fix every last defect in that report and the MegaBridge would still not be sound. Since we never inspected all of the critical welds in the first place, fixing only the defects we reported is insufficient. It is not enough for us to merely retest the ones we reported as defective. We need to test all of them.
"Also, the fact that you are making pervasive changes to the road surface, the suspension materials and the pillar diameters, far-reaching design changes which were clearly rushed and have not gone through normal review procedures, I'm afraid that all of our previous tests are now invalidated as well.
"Additionally, many of your proposals either avoid addressing the flaws, paper around the flaws, or even introduce new flaws. We need to re-certify the new design before we can even think about retesting the bridge.
"However considering the huge number of defects reported, the even larger number of defects undetected because of lack of inspection time, the questionable competency of the newly-minted inspectors, and overt corruption of the process by MegaCorp, my recommendation would be to tear this thing down before it falls over and hurts someone."
Update: I just saw the press release about the cease and desist letter. I think folks need to read the magistrate judge's Report and Recommendations itself to properly analyze the matter. It's not on PACER yet, and the law firm putting out the press release doesn't provide the original, only an edited text version, but even if we accept the accuracy of the version, which I don't until I can compare it with the original, here's what the magistrate judge found:
Under the DMCA, the copyright holder need only plead a prima facie case of copyright infringement. In re: Verizon Internet Servs., Inc., 257 F. Supp. 2d 244, 263 (D.D.C. 2003). A certificate of registration of a copyright constitutes prima facie evidence of the validity of the copyright and facts stated in the certificate. 17 U.S.C. Section 410(c). Melaleuca has registered the Sheppard Letter with the Copyright Office. See Supplemental Filing Re: Copyright Registration Certificate for Sheppard Letter, Ex. 1 (Docket No. 18-2). This is prima facie evidence that the Sheppard Letter is copyrighted and satisfies the first prong of demonstrating a prima facie case of copyright infringement. 43SB has valid arguments and enforcing this subpoena pre-litigation may have far-reaching consequences, therefore some preliminary examination of the potential claim is necessary. However, the Court will not go into an in-depth analysis of the merits of a copyright infringement claim in determining whether to quash this subpoena. It is sufficient in this instance that Melaleuca has registered the Sheppard Letter with the Copyright Office.
The party seeking a subpoena must also make a prima facie showing of copying of constituent elements of the work that are original. See In re: Verizon Servs., Inc., 257 F. Supp. 2d 244, 263 (D.D.C. 2003). The entire Sheppard Letter was posted on the Website by user "d2." This suffices to show a copying of constituent elements of the work that are original by user "d2." Therefore, the Court finds that all the elements necessary for a subpoena to issue under 17 U.S.C. Section 512(h), including the notification requirements of section 512(c)(3)(A) and the prima facie case, have been satisfied for user "d2." The Court recommends that the motion to quash with respect to "d2" be denied.
Written objections to this Report and Recommendation must be filed within ten (10) days pursuant to 28 U.S.C. Section 636(b)(1) and Local Rule 72.1, or as a result of failing to do so, that party may waive the right to raise factual and/or legal objections to the United States Court of Appeals for the Ninth Circuit.
In short, it's about a subpoena, whether a letter registered with the US Copyright Office, is sufficient to permit the issuing of a subpoena under the DMCA. It specifically does *not* rule on the copyrightability of the letter itself and says that has to happen in a more in-depth analysis. That will have to be figured out later. And even this report is appealable immediately or if preferred objections can be filed in Idaho. In short, I think the press release went a bit over the top in its analysis of what it means, but read it for yourself and you can form your own opinion.