To solve this issue I had to create a fat library of my custom framework again using xcode 11 tools.
To do that I did the following:
1) Build YourCustomFramework target for iOS simulator and extract framework from products folder on your desktop.
Xcode ▸ DerivedData ▸ Your Project ▸ Build ▸ Products ▸ Release-iphonesimulator
2) Build YourCustomFramework target for Generic iOS Device and extract framework from products folder on your desktop.
Xcode ▸ DerivedData ▸ Your Project ▸ Build ▸ Products ▸ Release-iphoneos
3) Rename the simulator generated framework to YourCustomFramework-sim.framework so that it is distinguishable later.
4) Use the lipo command to combine both binaries into a single fat binary file. (cd to your desktop or wherever your custom framework file is located)
$lipo -create ./YourCustomFramework-sim.framework/YourCustomFramework ./YourCustomFramework.framework/YourCustomFramework -output ./YourCustomFramework
5) Copy YourCustomFramework binary file created in above step and replace it with the binary in YourCustomFramework.framework folder.
6) From folder
YourCustomFramework-sim.framework/Modules/YourCustomFramework.swiftmodule/
copy all of the modules and paste them to
YourCustomFramework.framework/Modules/YourCustomFramework.swiftmodule/
This should solve your issue.