# How to Upgrade Band and Yoda Software to Version v1.2.8-rc0

This guide explains how to upgrade bandd and yoda program that currently running. The aim of this guide is to allow validators on BandChain to smoothly update their yoda service without any significant downtime.

## Required update:
- New bandd version that using a new wasmer runtime and optimize how to compile oracle script.

## Optional feature:
- Expose prometheus metric endpoint to track yoda stat.

### Step 1: Upgrade Your Band and Yoda Software to the Latest Version

cd $HOME/bandchain/chain
git fetch
git checkout v1.2.8-rc0

make install

# Check that the correction version of bandd and bandcli is installed

bandd version 
1.2.8-rc0

### Step 2: Stop the `yoda` process

sudo systemctl stop yoda.service

### Step 3: Restart the `bandd` process

sudo systemctl restart bandd.service

Make sure `bandd` service continues to mine blocks by running `journalctl -f -u bandd.service`

### Step 4: Setup Yoda Config for Prometheus (optional)

Expose prometheus metric endpoint on custom port

yoda config metrics-listen-addr 127.0.0.1:<YOUR_PORT>

### Step 6: Start `yoda` back after `bandd` has started processing the blocks

sudo systemctl start yoda

### Step 7: Checking Prometheus Metrics (optional)

Check your prometheus metric by `curl 'http://localhost:<YOUR_PORT>/metrics'`

If all goes well, you should see the metrics like this

yoda_reports_error_total 0
# HELP yoda_reports_handling_count Number of reports currently being handled
# TYPE yoda_reports_handling_count gauge
yoda_reports_handling_count 0
# HELP yoda_reports_pending_count Number of reports currently pending for submission
# TYPE yoda_reports_pending_count gauge
yoda_reports_pending_count 1
# HELP yoda_reports_submitted_total Number of reports submitted since last yoda restart
# TYPE yoda_reports_submitted_total counter
yoda_reports_submitted_total 3