I've not seen any mention of this here, so it might be off-topic, if so, sorry in advance. If you use GPS for time synchronization, this might be important. The Juniper ACX500 series and the Cisco 819 both have an embedded GPS receivers, for example.

At 23:59:42 UTC on 4/6/2019 (Midnight GPS time, which differs by 18 leap-seconds from UTC) , the 10-bit GPS Week Number broadcast by the constellation will reset to zero for the second time since the beginning of GPS on 1/6/1980.

Ken
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GPS Week Number Rollover (WNRO)