# Migration of Devices Without Ability to Rejoin

**URL:** <https://www.thethingsnetwork.org/forum/t/migration-of-devices-without-ability-to-rejoin/44515>\
**Category:** Migrating Devices to V3\
**Created:** [February 18, 2021, 8:35pm UTC](https://www.thethingsnetwork.org/forum/t/migration-of-devices-without-ability-to-rejoin/44515 "2021-02-18T20:35:11Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![bluejedi](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/bluejedi/32/44639_2.png) [@bluejedi](https://www.thethingsnetwork.org/forum/u/bluejedi)\
**Post date:** [February 18, 2021, 9:45pm UTC](https://www.thethingsnetwork.org/forum/t/migration-of-devices-without-ability-to-rejoin/44515/7 "2021-02-18T21:45:43Z")

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Based on the following information:

> [@The Things Network upgrade to V3](https://www.thethingsnetwork.org/forum/t/the-things-network-upgrade-to-v3/43256/1):
>
> - It is highly recommended to migrate devices _without_ the security session. This means that devices have to rejoin on V3. This is because we changed some LoRaWAN settings and we issue a new DevAddr that points to the V3 clusters. Packet Broker does not route traffic from the current V2 DevAddr ranges to the V3 clusters. Most devices will automatically revert to join mode when they figured out they lost link, by link check MAC commands, expecting acknowledgements sometimes, etc
> - If you really need to retain your LoRaWAN security session, you need to make sure that the gateways covering your end devices are already connected to a V3 cluster, because your old DevAddr does not get routed by Packet Broker from V2 to V3. Note that migrating gateways already may break deployments from other community members

It appears that migrating devices ‘including security session’ should be possible under certain conditions. I personally have no experience with these migration tool(s), but TTI staff probably will.

And please provide _detailed information_ about your case and devices (if necessary ask the developers). Without it this thread will only turn into a cat and mouse game.  
Don’t make others have to guess and ask for more information that you can already provide yourself.

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