Updating a custom variable in a plugin

[murali-baskar]

Hello,
We have a plugin that updates the custom variables. This is used to dynamically set the AWS region based on the stage value. E.g. if stage = dev then awsRegion= us-east-2, if stage = test then awsRegion = us-west-1 and so on..
The syntax in the plugin is something like: this.serverless.service.custom.awsRegion= "us-west-1";
After upgrading the serverless version to 3.x, the variable is not getting updated as expected and results in deployment error due to incorrect region. Is this the correct approach to update the variables in 3.x or is there a better/correct way to do it? Any help help on this issue is much appreciated. Thank you!