The updates for the LG V30 US988 unlocked model would be issued by LG and not Verizon Wireless. The VZW update assistant doesn't recognize the IMEI number because it isn't the Verizon Wireless model (VS996). You should check with LG to see what the most recent update is available.
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Ann154, this is a great recommendation. Stringer3, LG has a Mobile Support Tool that allows you to update the software and firmware: https://www.lg.com/us/support-mobile/lg-US998-Unlocked. Please try to update the software at the link provided and circle back with us if you are still having trouble.
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