[Docs] Moderato migration notes (RPC + Validator): binary version, datadir reset, and consensus port tips

[happylanding9]

Describe the change

Hi Tempo team — sharing a few docs/UX gaps I hit while migrating from the old testnet (Andantino / 42429) to Moderato (42431). None of these are protocol bugs, but they cost a lot of time during onboarding and seem easy to prevent with a short checklist in the docs.

1) “--chain moderato” fails on older tempo binaries (and systemd makes this easy to miss)

I initially had multiple tempo binaries on the server. My shell had a newer one, but systemd ExecStart still pointed to an older local build. Result: the service kept restarting and failing with:

Jan 28 14:48:36 tempo: error: Invalid value 'moderato' for --chain <CHAIN_OR_PATH>...
[possible values: testnet]

The binary at the ExecStart path was:
/root/tempo-node/tempo/target/release/tempo --version
Tempo Version: 0.8.2 (Commit 7119dc2)

Suggestion:

• Please add a clear minimum tempo version requirement for Moderato (--chain moderato, tempo download --chain moderato)
• And a quick note that systemd may use a different binary than which tempo (recommend using a stable path like /usr/local/bin/tempo in examples)

2) Reusing old datadir when switching chains → genesis hash mismatch

After switching chains, reusing the old datadir/db caused a fatal startup error:

genesis hash in the storage does not match the specified chainspec...

Suggestion:

• Add a prominent warning in the migration flow: switching chains requires a fresh datadir (or deleting <datadir>/db), otherwise genesis mismatch is expected.
• A tiny “migration snippet” would help a lot.

3) Validator consensus port (IP:8000) guidance would benefit from a small “ports + verify” section

When setting up validator inbound/outbound (often IP:8000), it’s easy to end up binding consensus only to localhost and wonder why it’s unreachable.

Suggestion:

• Document --consensus.listen-address 0.0.0.0:8000 explicitly (and confirm whether 8000 is the standard required inbound port)
• Provide a ports checklist:
  • 30303/TCP + 30303/UDP (execution P2P)
  • 8000/TCP (consensus inbound/outbound, if applicable)
• Add a one-liner verification command:
  sudo ss -lntup | grep -i tempo

Environment:

• Ubuntu 22.04.5 LTS (Jammy)
• systemd
• Migration: Andantino (42429) -> Moderato (42431)

Docs reference:

• https://docs.tempo.xyz/guide/node/validator

Additional context

No response