---
title: "Traefik Migration Documentation"
description: "Learn the steps needed to migrate to new Traefik Proxy v3 versions. Read the technical documentation."
---

# Migration: Steps needed between the versions

This guide provides detailed migration steps for upgrading between different Traefik v3 versions. Each section covers breaking changes, deprecations, and configuration updates required for a smooth transition.

---

## v3.0 to v3.1

### Kubernetes Provider RBACs

Starting with v3.1, Traefik's Kubernetes Providers use the [EndpointSlices API](https://kubernetes.io/docs/concepts/services-networking/endpoint-slices/) (requires Kubernetes >=v1.21) for service endpoint discovery. This change also introduces NodePort load-balancing capabilities.

The following RBAC updates are required for all Kubernetes providers:

- Remove endpoints permissions and add endpointslices:

```yaml
# Remove this section from your RBAC
# - apiGroups: [""]
#   resources: ["endpoints"]
#   verbs: ["get", "list", "watch"]

# Add this section instead
- apiGroups:
    - discovery.k8s.io
  resources:
    - endpointslices
  verbs:
    - list
    - watch
```

- Add nodes permissions for NodePort support:

```yaml
- apiGroups:
    - ""
  resources:
    - nodes
  verbs:
    - get
    - list
    - watch
```

!!! note "Affected Providers"
    These changes apply to:
    
    - [KubernetesIngress](../routing/providers/kubernetes-ingress.md#configuration-example) provider
    - [KubernetesCRD](../reference/dynamic-configuration/kubernetes-crd.md#rbac) provider  
    - [KubernetesGateway](../reference/dynamic-configuration/kubernetes-gateway-rbac.yml) provider

#### Gateway API: KubernetesGateway Provider

The KubernetesGateway Provider is no longer experimental in v3.1 and can be enabled without the `experimental.kubernetesgateway` option.

**Deprecated Configuration:**

??? example "Experimental kubernetesgateway option (deprecated)"

    ```yaml tab="File (YAML)"
    experimental:
      kubernetesgateway: true
    ```

    ```toml tab="File (TOML)"
    [experimental]
        kubernetesgateway=true
    ```

    ```bash tab="CLI"
    --experimental.kubernetesgateway=true
    ```

**Migration Steps:**

1. Remove the `kubernetesgateway` option from the experimental section
2. Configure the provider using the [KubernetesGateway Provider documentation](../providers/kubernetes-gateway.md)

---

## v3.1.0 to v3.1.1

### IngressClass Lookup

The `disableIngressClassLookup` option has been deprecated and will be removed in the next major version.

**Migration Required:**

- **Old:** `disableIngressClassLookup`
- **New:** `disableClusterScopeResources`

The new option provides broader control over cluster scope resources discovery, including both IngressClass and Nodes resources.

---

## v3.1 to v3.2

### Kubernetes CRD Provider

New optional fields have been added to several CRDs. These updates are backward compatible and only add new functionality.

**Apply the latest CRDs:**

```shell
kubectl apply -f https://raw.githubusercontent.com/traefik/traefik/v3.3/docs/content/reference/dynamic-configuration/kubernetes-crd-definition-v1.yml
```

**Updated Resources:**

- [TraefikService](../routing/services/index.md#mirroring-service) ([PR #11032](https://github.com/traefik/traefik/pull/11032))
- [RateLimit](../middlewares/http/ratelimit.md) & [InFlightReq](../middlewares/http/inflightreq.md) middlewares ([PR #9747](https://github.com/traefik/traefik/pull/9747))
- [Compress](../middlewares/http/compress.md) middleware ([PR #10943](https://github.com/traefik/traefik/pull/10943))

### Kubernetes Gateway Provider Standard Channel

Starting with v3.2, the Kubernetes Gateway Provider now supports [GRPCRoute](https://gateway-api.sigs.k8s.io/api-types/grpcroute/) resources.

Therefore, in the corresponding RBACs (see [KubernetesGateway](../reference/dynamic-configuration/kubernetes-gateway-rbac.yml) provider RBACs),
the `grcroutes` and `grpcroutes/status` rights have to be added.

**Required RBAC Updates:**

```yaml
...
- apiGroups:
    - gateway.networking.k8s.io
  resources:
    - grpcroutes
  verbs:
    - get
    - list
    - watch
- apiGroups:
    - gateway.networking.k8s.io
  resources:
    - grpcroutes/status
  verbs:
    - update
...
```

### Kubernetes Gateway Provider Experimental Channel

Due to breaking changes in Kubernetes Gateway [v1.2.0-rc1](https://github.com/kubernetes-sigs/gateway-api/releases/tag/v1.2.0-rc1), Traefik v3.3 only supports Kubernetes Gateway v1.2.x when experimental features are enabled.

**New Feature: BackendTLSPolicy Support**

The provider now supports [BackendTLSPolicy](https://gateway-api.sigs.k8s.io/api-types/backendtlspolicy/) resources.

Therefore, in the corresponding RBACs (see [KubernetesGateway](../reference/dynamic-configuration/kubernetes-gateway-rbac.yml) provider RBACs),
the `backendtlspolicies` and `backendtlspolicies/status` rights have to be added.

**Required RBAC Updates:**

```yaml
  ...
  - apiGroups:
      - ""
    resources:
      - configmaps
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - gateway.networking.k8s.io
    resources:
      - backendtlspolicies
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - gateway.networking.k8s.io
    resources:
      - backendtlspolicies/status
    verbs:
      - update
  ...
```

---

## v3.2.1

### `X-Forwarded-Prefix` Header Changes

In v3.2.1, the `X-Forwarded-Prefix` header is now handled like other `X-Forwarded-*` headers - Traefik removes it when sent from untrusted sources.

This change improves security by preventing header spoofing from untrusted clients. Refer to the [Forwarded headers documentation](../routing/entrypoints.md#forwarded-headers) for configuration details.

---

## v3.2.2

### Swarm Provider Label Updates

In v3.2.2, Swarm-specific labels have been deprecated and will be removed in a future version.

**Migration Required:**

| Deprecated Label | New Label |
|------------------|-----------|
| `traefik.docker.network` | `traefik.swarm.network` |
| `traefik.docker.lbswarm` | `traefik.swarm.lbswarm` |

---

## v3.2 to v3.3

### ACME DNS Certificate Resolver

In v3.3, DNS challenge configuration options have been reorganized for better clarity.

**Migration Required:**

| Deprecated Option | New Option |
|-------------------|------------|
| `acme.dnsChallenge.delaybeforecheck` | `acme.dnsChallenge.propagation.delayBeforeChecks` |
| `acme.dnsChallenge.disablepropagationcheck` | `acme.dnsChallenge.propagation.disableChecks` |

### Tracing Global Attributes

In v3.3, the tracing configuration has been clarified to better reflect its purpose.

**Migration Required:**

- **Old:** `tracing.globalAttributes`
- **New:** `tracing.resourceAttributes`

The old option name was misleading as it specifically adds resource attributes for the collector, not global span attributes.

---

## v3.3.4

### OpenTelemetry Request Duration Metric

In v3.3.4, the OpenTelemetry Request Duration metric unit has been standardized to match other providers and naming conventions.

**Change Details:**

- **Metric:** `traefik_(entrypoint|router|service)_request_duration_seconds`
- **Old Unit:** Milliseconds  
- **New Unit:** Seconds

This change ensures consistency across all metrics providers and follows standard naming conventions.

---

## v3.3.5

### Compress Middleware Default Encodings

In v3.3.5, the default compression algorithms have been reordered to favor gzip compression.

**New Default:** `gzip, br, zstd`

This change affects requests that either:

- Don't specify preferred algorithms in the `Accept-Encoding` header
- Have no order preference in their `Accept-Encoding` header

The reordering helps ensure better compatibility with older clients that may not support newer compression algorithms.

---

## v3.3.6

### Request Path Sanitization

Starting with v3.3.6, incoming request paths are now automatically cleaned before processing for security and consistency.

**What's Changed:**

The following path segments are now interpreted and collapsed:

- `/../` (parent directory references)
- `/./` (current directory references)  
- Duplicate slash segments (`//`)

**Disabling Sanitization:**

```yaml
# EntryPoint HTTP configuration
entryPoints:
  web:
    address: ":80"
    http:
      sanitizePath: false  # Not recommended
```

!!! danger "Security Warning"
    Setting `sanitizePath: false` is not safe. This option should only be used with legacy clients that don't properly URL-encode data. Always ensure requests are properly URL-encoded instead of disabling this security feature.

**Example Risk:**
Base64 data containing "/" characters can lead to unsafe routing when path sanitization is disabled and the data isn't URL-encoded.

---

## v3.3 to v3.4

### Kubernetes CRD Provider

#### Load-Balancing Strategy Updates

Starting with v3.4, HTTP service definitions now support additional load-balancing strategies for better traffic distribution.

**Apply Updated CRDs:**

```shell
kubectl apply -f https://raw.githubusercontent.com/traefik/traefik/v3.4/docs/content/reference/dynamic-configuration/kubernetes-crd-definition-v1.yml
```

**New Strategy Values:**

- `wrr` (Weighted Round Robin)
- `p2c` (Power of Two Choices)

!!! warning "Deprecation"
    The `RoundRobin` strategy is deprecated but still supported (equivalent to `wrr`). It will be removed in the next major release.

Refer to the [HTTP Services Load Balancing documentation](../routing/services/index.md#load-balancing-strategy) for detailed information.

#### ServersTransport CA Certificate Configuration

A new `rootCAs` option has been added to the `ServersTransport` and `ServersTransportTCP` CRDs. It supports both ConfigMaps and Secrets for CA certificates and replaces the `rootCAsSecrets` option.

**Apply Updates:**

```shell
# Update CRDs
kubectl apply -f https://raw.githubusercontent.com/traefik/traefik/v3.4/docs/content/reference/dynamic-configuration/kubernetes-crd-definition-v1.yml

# Update RBACs
kubectl apply -f https://raw.githubusercontent.com/traefik/traefik/v3.4/docs/content/reference/dynamic-configuration/kubernetes-crd-rbac.yml
```

**New Configuration Format:**

```yaml
---
apiVersion: traefik.io/v1alpha1
kind: ServersTransport
metadata:
  name: foo
  namespace: bar
spec:
  rootCAs:
    - configMap: ca-config-map
    - secret: ca-secret
      
---      
apiVersion: traefik.io/v1alpha1
kind: ServersTransportTCP
metadata:
  name: foo
  namespace: bar
spec:
  rootCAs:
    - configMap: ca-config-map
    - secret: ca-secret
```

!!! warning "Deprecation"
    The `rootCAsSecrets` option (Secrets only) is still supported but deprecated. It will be removed in the next major release.

### Rule Syntax Configuration

In v3.4, rule syntax configuration options will be removed in the next major version.

**Deprecated Options:**

- `core.defaultRuleSyntax` (static configuration)
- `ruleSyntax` (router option)

These options were transitional helpers for migrating from v2 to v3 syntax. Please ensure all router rules use v3 syntax before the next major release.

---

## v3.4.1

### Request Path Normalization

Starting with v3.4.1, request paths are now normalized according to RFC 3986 standards for better consistency and security.

**Normalization Process:**

1. **Unreserved Character Decoding:** Characters like `%2E` (.) are decoded to their literal form
2. **Case Normalization:** Percent-encoded characters are uppercased (`%2e` becomes `%2E`)

This follows [RFC 3986 percent-encoding normalization](https://datatracker.ietf.org/doc/html/rfc3986#section-6.2.2.2) and [case normalization](https://datatracker.ietf.org/doc/html/rfc3986#section-6.2.2.1) standards.

**Processing Order:**

1. Path normalization (cannot be disabled)
2. Path sanitization (if enabled)

### Reserved Character Handling in Routing

Starting with v3.4.1, reserved characters (per [RFC 3986](https://datatracker.ietf.org/doc/html/rfc3986#section-2.2)) remain encoded during router rule matching to prevent routing ambiguity.

**Why This Matters:**
Reserved characters change the meaning of request paths when decoded. Keeping them encoded during routing prevents security vulnerabilities and ensures predictable routing behavior.

### Request Path Matching Examples

The following table illustrates how path matching behavior has changed:

| Request Path      | Router Rule                  | Traefik v3.4.0 | Traefik v3.4.1 | Explanation                                           |
|-------------------|------------------------------|----------------|----------------|-------------------------------------------------------|
| `/foo%2Fbar`      | ```PathPrefix(`/foo/bar`)``` | Match          | No match       | `%2F` (/) stays encoded, preventing false matches     |
| `/foo/../bar`     | ```PathPrefix(`/foo`)```     | No match       | No match       | Path traversal is sanitized away                      |
| `/foo/../bar`     | ```PathPrefix(`/bar`)```     | Match          | Match          | Resolves to `/bar` after sanitization                 |
| `/foo/%2E%2E/bar` | ```PathPrefix(`/foo`)```     | Match          | No match       | Encoded dots normalized then sanitized                |
| `/foo/%2E%2E/bar` | ```PathPrefix(`/bar`)```     | No match       | Match          | Resolves to `/bar` after normalization + sanitization |

## v3.4.5

### MultiPath TCP

Since `v3.4.5`, the MultiPath TCP support introduced with `v3.4.2` has been removed.
It appears that enabling MPTCP on some platforms can cause Traefik to stop with the following error logs message:

- `set tcp X.X.X.X:X->X.X.X.X:X: setsockopt: operation not supported`

However, it can be re-enabled by setting the `multipathtcp` variable in the GODEBUG environment variable, see the related [go documentation](https://go.dev/doc/godebug#go-124).

## v3.5.0

### Observability

#### TraceVerbosity on Routers and Entrypoints

Starting with `v3.5.0`, a new `traceVerbosity` option is available for both entrypoints and routers.
This option allows you to control the level of detail for tracing spans.
Routers can override the value inherited from their entrypoint.

**Impact:**

- If you rely on tracing, review your configuration to explicitly set the desired verbosity level.
- Existing configurations will default to `minimal` unless overridden, which will result in fewer spans being generated than before.

Possible values are:

- `minimal`: produces a single server span and one client span for each request processed by a router.
- `detailed`: enables the creation of additional spans for each middleware executed for each request processed by a router.

See the updated documentation for [entrypoints](../reference/install-configuration/entrypoints.md) and [dynamic routers](../reference/routing-configuration/http/routing/observability.md#traceverbosity).

#### K8s Resource Attributes

Since `v3.5.0`, the semconv attributes `k8s.pod.name` and `k8s.pod.uid` are injected automatically in OTel resource attributes when OTel tracing/logs/metrics are enabled.

For that purpose, the following right has to be added to the Traefik Kubernetes RBACs:

```yaml
  ...
  - apiGroups:
      - ""
    resources:
      - pods
    verbs:
      - get
  ...
```

---

## v3.5.2

### Deprecation of ProxyProtocol option

Starting with `v3.5.2`, the `proxyProtocol` option for TCP LoadBalancer is deprecated.
This option can now be configured at the `TCPServersTransport` level, please check out the [documentation](../reference/routing-configuration/tcp/serverstransport.md) for more details.

#### Kubernetes CRD Provider

To use the new `proxyprotocol` option in the Kubernetes CRD provider, you need to update your CRDs.

**Apply Updated CRDs:**

```shell
kubectl apply -f https://raw.githubusercontent.com/traefik/traefik/v3.5/docs/content/reference/dynamic-configuration/kubernetes-crd-definition-v1.yml
```

## v3.5.4

### Certificate Metric Renamed with OpenTelemetry 

Starting with `v3.5.4`, and when using OpenTelemetry, the `traefik_tls_certs_not_after_milliseconds` metric is renamed to `traefik_tls_certs_not_after_seconds`.
This change aligns the metric name with its real unit precision, which is in seconds. 
