@BrutalBirdie Gemini says:
Conclusion based purely on this AGPL-3.0 license text:
If the Rallly code that implements the user limit and the nag banner is itself licensed under this AGPL-3.0, then:
Yes, a user or organization (like Cloudron, if they chose) can legally fork Rallly.
Yes, they can modify the AGPL-3.0 licensed source code to remove the multi-user licensing check and the associated nag banner. This would be considered removing a "further restriction" as permitted by Section 7.
They must still comply with all other AGPL-3.0 terms when they distribute or provide network access to their modified version:
Clearly state that their version is modified (Section 5a).
State that their modified version is released under the AGPL-3.0 (Section 5b).
Display "Appropriate Legal Notices" (the AGPL ones, not Rallly's proprietary ones) in the UI (Section 5d).
Provide the Corresponding Source of their modified version to users interacting with it over a network (Section 13).
Keep original copyright notices and AGPL license information intact.
The Neo4j precedent mentioned in the forum discussion is less relevant here if Rallly is genuinely distributing the entirety of this V4 code (including the restriction mechanism) under this standard, unmodified AGPL-3.0. The Neo4j case involved a license that was AGPLv3 plus a "Commons Clause," which was a significant alteration/addition to the AGPL terms. If Rallly is just using plain AGPL-3.0, then plain AGPL-3.0 rules apply.
In summary: The AGPL-3.0 is designed to prevent exactly this kind of "bait-and-switch" where software is offered as "free" under a strong copyleft license, but then functional restrictions are baked in that users cannot remove. The license explicitly gives users the right to remove such "further restrictions."