I am trying to add a filter to an already existing subscription to an SNS topic. When I deploy the stack using Cloud formation template, it gives me error –

Using CloudFormation, I’m trying to deploy an SNS topic with an ArchivePolicy of 90 days. From the AWS docs, this Property is “Type: Json” but I can find no reference to its structure. I did find this recent AWS article, that hints at the structure containing a single key named “MessageRetentionPeriod” and its value an integer in days.