As announced at https://www.jelurida.com/news/future-nxt , with this release
we are implementing the forgers voting for the proposed migration of Nxt
to a new Ardor child chain on mainnet. The migration signalling and shutdown
was successfully tested with the previous release on Nxt testnet, which is now
stopped and not producing new blocks.

All mainnet nodes who support the Nxt migration must upgrade to this release
before the hardfork scheduled for block 5915915, the "migration signalling
height" expected around Nov 23, 2025. After this height, nodes forging with
this release will generate blocks with version 4 (current block version is 3),
but will also accept as valid blocks with version 3, provided that the
previous block is not version 4. Nodes who do not upgrade to this release will
continue to generate version 3 blocks only and refuse to switch to a fork
containing version 4 blocks, while nodes running this release will consider
both forks as valid and switch to whichever grows to a better cumulative
difficulty.

1440 blocks after the migration signalling height, the "migration decision
height" is reached. After this height, if the last block is version 4, the
migration decision will be considered approved and at block 6000000, expected
around Jan 20, 2026, the "snapshot height" is reached, after which no more
Nxt mainnet blocks will be generated or accepted. Shortly after, we will do an
Ardor mainnet release which will enable the new Nxt child chain based on a
snapshot of the Nxt blockchain as of that final height.

The code that will be used to generate the snapshot is included in this
release under src/java/nxt/addons/ChildChainSnapshot.java so that anyone will
be able to independently run it and verify the snapshot balances.

This the final of more than 160 Nxt software releases we have done for the
last 12 years. It has been a long journey. See you over at Ardor!

