I'm not sure, but `NoncurrentVersionExpiration.NoncurrentDays` seems to be an alternative to `NoncurrentVersionExpirationInDays`. https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-s3-bucket-lifecycleconfig-rule.html#cfn-s3-bucket-lifecycleconfig-rule-noncurrentversionexpirationindays
I'm not sure, but
NoncurrentVersionExpiration.NoncurrentDaysseems to be an alternative toNoncurrentVersionExpirationInDays.https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-s3-bucket-lifecycleconfig-rule.html#cfn-s3-bucket-lifecycleconfig-rule-noncurrentversionexpirationindays