Q: My MacBook Pro (pre-2016) has Thunderbolt 2 connections. How can I use the PowerPack 20000 to charge my MacBook Pro?
A: Apple has switched to Thunderbolt 3 for their MacBook Pro's since 2016. Compared to its predecessor Thunderbolt 2, the upgrade to the Thunderbolt 3 involves not only a physical change of the shape and pin configurations of the connector, but also a software upgrade to an open charging standard called USB Power Delivery. The ZMI PowerPack 20000 is designed to work with laptops that are enabled for the USB Power Delivery. Unfortunately, your MacBook Pro with the Thunderbolt 2 port does not support the newer USB Power Delivery charging standard, so your laptop won't be able to charge with the PowerPack 20000. There may be connector adapters out there, but they can't resolve the incompatibility due to the change to the underlying charging control software made by Apple.