You'll need to be on stock (unrooted) LJC to do the update.
Also... for now if you want to re-root:
1) Install custom recovery of your choice
2) Flash the following .ZIP:
...and you'll be all set.
I'm hoping to see a full TAR available soon where we can make proper one clicks.
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If you like the various efforts and want to help get new devices on board, donations really help - whether to me or to a project.
Many folks spend a great amount of time to bring you the stuff you love - and appreciate when people give back.
Please continue to thank and support those who bring these great things to our devices!