Not all old nodes are disconnected after the update period of time
Motivation
After each hard fork release we have an update period. Old (not updated) nodes should be disconnected after that period of time. Then it's safe to turn on enforcement and other spork features. During the release 0.12.4.1 after 20 days of the update period not all old nodes were cut off from the network.
Suggestion
Research and reproduce in the testnet release workflow. Fix the old nodes disconnection process.
Possible solutions/fixes
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