Please spread this like butter, so all late Minecrafters can take up the offer! I wasn't aware that the free upgrade was still available, so please accept my apologies for previous mis-information. :x :)
From the Official Minecraft website:
"If you’re still playing/own a copy of Minecraft: Xbox One Edition, then you can still update to the Bedrock version, absolutely free! You’ve been able to do this since we released the Better Together update, but this offer won’t last forever.
Existing Minecraft: Xbox One Edition players now have until November 30, 2019 to redeem their free update to the Bedrock version.
Luckily, updating couldn’t be easier! You’ll need to login to your Xbox profile on your console. If you own a physical copy of Minecraft: Xbox One Edition, and you’ve played five hours in the last twelve months, or bought DLC at any time, then you're entitled to a free update to the Bedrock version.
If you haven't played for five hours in the last 12 months/bought any DLC, you can fulfill either of the conditions (it’s a pretty good excuse to play Minecraft for five hours) before November 30 2019.
You will receive a 5x5 code via Xbox messaging that lets you redeem the Bedrock version of Minecraft. Please be prepared for a short wait to receive your code, as it could take a few weeks while our team processes redemption requests."