After this suggestion I looked at the proguard configuration in more detail and there was indeed a mistake:
I'm not sure if this is necessary, but if so, the name of the entire Integer class is missing here.
public Integer toUnderlyingValue();
It should be:
public java.lang.Integer toUnderlyingValue();
These rules will be sufficient to keep all required things from the helper class.
-keep enum pl.patryk_f.extension.helpers.MyIcon {
public protected *;
public static **[] values();
public static ** valueOf(java.lang.String);
}FAST will handle it by default from the next update v1.2.8.
An update is available v1.2.8Date built: 13.11.24.15.09
Wasn't this introduced in an earlier version?
FAST was keeping helper classes, but there was an issue. I've fixed it in v.1.2.8. You could also do the same from earlier version of FAST by using custom rules with the proguard-rules.pro.
Please make sure the @DesignerComponent annotation is present in your component source code.
The ListView component has changed, its new methods are not available in Fast.
If you are referring to these changes, you only need to add the dynamicanimation-1.0.0.jar into Fast/libs/appinventor/ and I will include it with the next update.
I mean the AndroidRuntime library.
Thanks, I've also noticed that after wrote my last reply. I think I've to build the AI2 source to get the latest AndroidRuntime.jar.
FAST will require a minimum of JDK11 after these changes are implemented.
Set proguard: true on fast.yml and run fast build -r command. The -o command is specially designed to optimize libraries of Kotlin when desugar_deps is enabled.
An update is available v2.0.0Date built: 22.11.24.00.52
Added Maven dependency resolver.
sync command has been optimized..gitignore file has been modified.AndroidRuntime.jar with these changes. 
Enter a new era of extension development with FAST 2.0, unlocking the full power of Maven like dependency management.
How to use resolver?
To see how to use remote dependencies, start a new project. Remember, whenever you add or change any remote libraries, you'll need to run fast sync and before running the fast build. However, you could use remote libraries in your old projects. Just you need to reconfigure the fast.yml to be compatible with FAST 2.0.
A clean installation of FAST 2.0 is required.
So, instead of updating I have to reinstall fast after uninstalling it?
Getting this
__ _
/ _| __ _ ___| |_
| |_ / _` / __| __|
| _| (_| \__ \ |_
|_| \__,_|___/\__| (v2.0.0)
- Fetching local dependencies
- Resolving compile-time dependencies
- Searching for required dependencies
x Failed to collect dependencies at org.jetbrains.kotlinx:kotlinx-coroutines-core:jar:1.7.1```
My fast.yml depndencies
compile_time: