Previously, the guidance on keepAlive was that we should set socketOptions.keepAlive : 0 in order to enable keepAlive and that would also set keepAliveInitialDelay to 0. In a recent change this was altered, now keepAlive is only set to true if keepAlive is > 0. That would mean everyone out there which was previously using keepAlive : 0 is now no longer using keepAlive (because 0 is not > 0).

Was that change meant to be a change in driver configuration. As recently as December the current suggestion was to set keepAlive : 0 to enable keepAlive see https://jira.mongodb.org/browse/NODE-614 . If it's an accident it should probably be reverted, if it's intentional you may want to call out that the setting changed and the docs should be updated to account.