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To help the clear separation of ecFlow4 and ecflow5 related settings, from version 5.2.3 ecFlowUI will use a new configuration directory. As a consequence, you can create a separate server list for ecFlowUI 4 and 5! .
You do not need to do anything, when you first start up ecFlowUI with a version >= 5.2.3 the new configuration directory will be automatically created for you by copying the contents of the old configuration directory.
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