I'm wondering if we couldn't increase the syntax version to avoid the API breakage. E.g., just introduce a new syntax {{annotatedhtml/5.1 }}with the new escaping and keep it the same on the old version. HTML stopped using version numbers but there are also HTML standards named HTML 5.1, HTML 5.2 and drafts of HTML 5.3 by the W3C that were eventually retired in favor of the "living" standard. If we have a better way to indicate that this is "our" version, I would prefer that but in any case there won't be any new standard HTML 5.1 that we then cannot support anymore - in fact, what we currently support is probably more something like HTML 5.3.