# Example: Major version upgrade from 1.1.1.0 to 1.2.0.2 with custom parameter groups
<a name="cfn-engine-update-1110-1202-custom"></a>

Find the `DBCluster` that you want to upgrade, and the template you used to create it. For example:

```
Description: Base Template to create Neptune Stack with Engine Version 1.1.1.0 using custom Parameter Groups 
Parameters:
  DbInstanceType:
    Description: Neptune DB instance type
    Type: String
    Default: db.r5.large
Resources:
  NeptuneDBClusterParameterGroup:
    Type: 'AWS::Neptune::DBClusterParameterGroup'
    Properties:
      Name: engineupgradetestcpg
      Family: neptune1
      Description: 'NeptuneDBClusterParameterGroup with family neptune1'
      Parameters:
        neptune_enable_audit_log: 0
  NeptuneDBParameterGroup:
    Type: 'AWS::Neptune::DBParameterGroup'
    Properties:
      Name: engineupgradetestpg
      Family: neptune1
      Description: 'NeptuneDBParameterGroup1 with family neptune1'
      Parameters:
        neptune_query_timeout: 20000
  NeptuneDBCluster:
    Type: 'AWS::Neptune::DBCluster'
    Properties:
      EngineVersion: 1.1.1.0
      DBClusterParameterGroupName:
        Ref: NeptuneDBClusterParameterGroup
    DependsOn:
      - NeptuneDBClusterParameterGroup
  NeptuneDBInstance:
    Type: 'AWS::Neptune::DBInstance'
    Properties:
      DBClusterIdentifier:
        Ref: NeptuneDBCluster
      DBInstanceClass:
        Ref: DbInstanceType
      DBParameterGroupName:
        Ref: NeptuneDBParameterGroup
    DependsOn:
      - NeptuneDBCluster
      - NeptuneDBParameterGroup
Outputs:
  DBClusterId:
    Description: Neptune Cluster Identifier
    Value:
      Ref: NeptuneDBCluster
```
+ Update the custom `DBClusterParameterGroup` family to the one used by the new engine version here `default.neptune1.2`).
+ For each `DBInstance` attached to the `DBCluster`, update the custom `DBParameterGroup` family to the one used by the new engine version (here `default.neptune1.2`).
+ Set the `DBInstanceParameterGroupName` property to the parameter group in that family (here `default.neptune1.2`).
+ Update the `EngineVersion` property from `1.1.0.0` to `1.2.0.2`.

The template should look like this:

```
Description: Template to upgrade major engine version to 1.2.0.2 by modifying existing custom parameter groups
Parameters:
  DbInstanceType:
    Description: Neptune DB instance type
    Type: String
    Default: db.r5.large
Resources:
  NeptuneDBClusterParameterGroup:
    Type: 'AWS::Neptune::DBClusterParameterGroup'
    Properties:
      Name: engineupgradetestcpgnew
      Family: neptune1.2
      Description: 'NeptuneDBClusterParameterGroup with family neptune1.2'
      Parameters:
        neptune_enable_audit_log: 0
  NeptuneDBParameterGroup:
    Type: 'AWS::Neptune::DBParameterGroup'
    Properties:
      Name: engineupgradetestpgnew
      Family: neptune1.2
      Description: 'NeptuneDBParameterGroup1 with family neptune1.2'
      Parameters:
        neptune_query_timeout: 20000
  NeptuneDBCluster:
    Type: 'AWS::Neptune::DBCluster'
    Properties:
      EngineVersion: 1.2.0.2
      DBClusterParameterGroupName:
        Ref: NeptuneDBClusterParameterGroup
      DBInstanceParameterGroupName:
        Ref: NeptuneDBParameterGroup
    DependsOn:
      - NeptuneDBClusterParameterGroup
  NeptuneDBInstance:
    Type: 'AWS::Neptune::DBInstance'
    Properties:
      DBClusterIdentifier:
        Ref: NeptuneDBCluster
      DBInstanceClass:
        Ref: DbInstanceType
      DBParameterGroupName:
        Ref: NeptuneDBParameterGroup
    DependsOn:
      - NeptuneDBCluster
      - NeptuneDBParameterGroup
Outputs:
  DBClusterId:
    Description: Neptune Cluster Identifier
    Value:
      Ref: NeptuneDBCluster
```

Now use CloudFormation to run the revised template.