They hit up a company I know because their web-crawler found a PDF that someone generated using their library over a decade ago.
https://beemanmuchmore.com/software-licensing-trolls-apryse-...
I'd avoid it.
https://itextpdf.com/how-buy/AGPLv3-license
Not really AGPL, they just advertise AGPL and mean something else. Avoid.
I personally think the AGPL would win, but it's not something I'd be willing to enter a legal battle over.
You already know that the licensor has his own, idiosyncratic interpretation. He either misunderstands the AGPL (probably clause 7 par 3 b), or he’s trying to deceive you. Both cases can easily lead to hostilities.
“ If the Program as you received it, or any part of it, contains a notice stating that it is governed by this License along with a term that is a further restriction, you may remove that term. ”
https://www.gnu.org/licenses/agpl-3.0.en.html
I think the expectation here is that commercial users purchase the AGPL opt-out.
Back in the day FlowPlayer (a JavaScript component to play videos on the web) used additional terms per GPL section 7 to force users of their unpaid version to keep their mark intact in the UI or for modifications keep a "based on FlowPlayer" in.
I followed the discussion on this back then and the consensus seemed to be, that this is in line with what section 7 of the GPL allows. I think there was even a statement of the FSF, but I could not find it anymore.
Of course the iText case is different, but I believe section 7 (especially 7b) allows a way to add terms for attribution.
Imagine if Bic said you had to write their name on every page you used one of their pens on.
https://github.com/LibrePDF/OpenPDFAs the commenters above note, the "upgrade" to AGPL was both highly profitable to Lowagie and caused many to shift to an open-source fork.
IMO forks are the great leveler; if your brand strength and your ongoing investment in engineering + community make a license shift viable (and if you retain the trust of your contributors) then everybody wins... but if you make a license shift and just rest on your laurels, forks will destroy your value. I don't know enough about the history to know what happened in this case, but based on the successful exit, I imagine it's somewhere between these two extremes.
I know historically PDFBox is a bit lower level whereas iText was a bit more user friendly, but that's not too big of a deal for me.
It's disgustingly fast and capable. In one project we crunched out 150k PDF documents in less than forty minutes from roughly 6 GB input data, on a mid laptop, including a fair bit of other file types related to those documents.
Fairly low level but not hard to get started with. You might have to wrap it in a module yourself if you're using those.
You could use both if you want, I've done it in toy projects when evaluating.
Most previous users of pdftk have probably migrated to qpdf by now.