Migration from 3.1 or 3.2 are supported, so you can upgrade directly to 4.0.
![[Warning]](common/images/admon-icons/warning.png){kind=icon} | Warning |
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In Rudder 4.0, we changed the default communication protocol between agent and server, but still stay compatible with the old protocol. Hence, you can perfectly keep using pre-4.0 agents with a 4.0 server. However, some networking issues may appear when using 4.0 agents with older servers with the reverse DNS lookup option disabled in the settings (Security → Use reverse DNS lookups on nodes to reinforce authentication to policy server). Therefore, you need to upgrade your server to 4.0 before upgrading the nodes so that the configuration distributed to the nodes include the use of the new protocol. |
