---
title: Prometheus agent upgrade to v2
source: https://docs.newrelic.com/docs/infrastructure/prometheus-integrations/migrations/v2-upgrade
---

When upgrading your Prometheus agent to `v2`, you'll need to account for its reliance on [Prometheus v3](https://prometheus.io/blog/2024/11/14/prometheus-3-0/). This means any [breaking changes](https://prometheus.io/docs/prometheus/latest/migration) introduced in Prometheus `v3` may also be present in your agent's `v2`. Specifically, Prometheus `v3` implements [strict](https://prometheus.io/docs/prometheus/latest/migration/#scrape-protocols) validation for the `Content-Type` header received during scraping. Unlike Prometheus `v2`, which would default to the standard Prometheus text protocol if the header was missing or invalid, Prometheus `v3` will fail the scrape under these conditions.

As a result, you must implement the following changes:

-   Both default Kubernetes jobs require `fallback_scrape_protocol: "PrometheusText0.0.4"` to be added to your specification. The default jobs for `config.kubernetes.jobs` should be configured as follows:

```yaml
- job_name_prefix: default
  fallback_scrape_protocol: "PrometheusText0.0.4"
  target_discovery:
    pod: true
    endpoints: true
    filter:
      annotations:
        prometheus.io/scrape: true
- job_name_prefix: newrelic
  fallback_scrape_protocol: "PrometheusText0.0.4"
  integrations_filter:
    enabled: false
  target_discovery:
    pod: true
    endpoints: true
    filter:
      annotations:
        newrelic.io/scrape: true
```

-   If you have any custom `config.static_targets.jobs` that target a Prometheus endpoint with missing or invalid headers, you must fix these to provide a valid header. As a temporary solution, you can add `fallback_scrape_protocol: "PrometheusText0.0.4"` to your specification.
-   Similarly, any custom `config.extra_scrape_configs` that target a Prometheus endpoint with missing or invalid headers must be fixed to provide a valid header. A temporary solution is to add `fallback_scrape_protocol: "PrometheusText0.0.4"` to your specification.

> #### ⚠️ IMPORTANT
>
> The `--reuse-values` flag is not supported if you upgrade from v1 to v2.