Hello, We have a 3 nodes cluster. We migrate our system from Nifi 1.23.2 to Nifi 2.4 with a stop at Nifi 1.28.1 as recommended in migration docs. Our flows were working as expected for the part 1.23.2 -> 1.28.1. We prepared the migration to Nifi 2 as explain in docs (remove variables and deprecated processors, modified CRON to remove the 7th digit...). Tests were OK. We then upgrade from 1.28.2 to Nifi 2.4. Just after this upgrade, our flows containing queues with round robin strategy getting stucked. One example, we ingest a XML file in the primary node (let's call it node0), do some stuffs, no problem. We then split the file by lines and send each lines to an EvaluateXPath to analyse the data. This queue between the SplitXML and EvaluateXPath has a round robin strategy to improve perfs. Just after the upgrade from 1.28.1 to Nifi 2.4 only one third of the lines were processed the lines that should be sent to the node1 et node2 are not processed and stay in the queue. Only reccords assigned to the primary node are processed (node0). Our admin did some tests to check if it was a network issue or certifs issue. It seems not as he succeed to execute some telnet and SLL command from node0 to node1 or node2. Zookeeper connection between nodes is OK as we manage to modify flows and having the modifications reported everywhere. After analysing logs he just found that there is an acknowlegement issue when node0 is trying to send flowfiles to node1/node2. We didn't find any known bug in Nifi 2.4 regarding the round robin strategy. Is there anyone elso who faced this kind of issue and managed to solve it.   Thank you very much for your help,   Olivier   ... View more