Problem with cloudformation stack update and launch template version / autoscaling group - aws-cloudformation

Question

I have a stack in cloudformation (ECS cluster, App LB, Autoscaling Group, launch templates, etc etc.) It all works fine and we have been using this in production and pre production environments for a while.
A problem recently arose while trying to push a stack update. I made some changes to UserData in the AWS::EC2::LaunchTemplate. If i launch a new stack from this template it works great.
BUT:
If i make a change set and apply a stack update cloudformation creates a NEW launch template version -however- the autoscaling group still references the OLD version.
Looking at the AWS docs for AWS::AutoScaling::AutoScalingGroup LaunchTemplateSpecification
I see:
"AWS CloudFormation does not support specifying $Latest, or $Default for the template version number."
Anyone wrangled w/ stack updates creating new versions of resources that need to be referenced elsewhere? I feel like i am missing something obvious.

Answer 1

yay, i'm dumb:
use Fn::GetAtt
ok, make fun of me for using json not yaml
...
"ECSAutoScalingGroup": {
"Type": "AWS::AutoScaling::AutoScalingGroup",
"Properties": {
"VPCZoneIdentifier": {"Ref" : "Subnets"},
"MinSize": "1",
"MaxSize": "10",
"DesiredCapacity": { "Ref": "DesiredInstanceCount" },
"MixedInstancesPolicy": {
"InstancesDistribution" :
{
"OnDemandBaseCapacity" : "0",
"OnDemandPercentageAboveBaseCapacity" : { "Ref" : "PercentOnDemand"}
},
"LaunchTemplate" : {
"LaunchTemplateSpecification" : {
"LaunchTemplateId" : {"Ref" : "ECSLaunchTemplate"},
"Version" : { "Fn::GetAtt" : [ "ECSLaunchTemplate", "LatestVersionNumber" ] }
},
"Overrides" : [ {"InstanceType": "m5.xlarge"},{"InstanceType": "t3.xlarge"},{"InstanceType": "m4.xlarge" },{"InstanceType": "r4.xlarge"},{"InstanceType": "c4.xlarge"}]
}
}
},
...