Further, we conjecture that the only non-trivial Byzantine-tolerantCRDT design is a grow-only HashDAG as it is done in the Matrix Event Graph

Consequently, if updateu2 depends on update u1, it could happen that somenodes deliver u1 before u2 and hence process bothupdates correctly, but other nodes may try to deliveru2 and fail because they have not yet delivered u1. Thissituation also leads to divergence.

Say a Byzantine node generates twodifferent updates u1 and u2 that create two differentitems with the same ID. If a node has already deliveredu1 and then subsequently delivers u2, the update u2will be rejected, but a node that has not previously de-livered u1 may accept u2. Since one node accepted u2and the other rejected it, those nodes fail to converge,even if we have eventual delivery