Support Dual Signing Using SHA1 & SHA256 Digest
In previous releases, you could choose the signature digest hashing algorithm only based on:

• Certificate Hash
• SHA-1
• SHA-256
In InstallShield 2018 SP1, along with the above signature digest hashing algorithms, you can now choose:

• Dual Signing - (SHA-1 and SHA-256) digest

Cudo's for finally adding dual signing support.

It took me a bit to figure this out. In your project, look at the certificate in the signing tab for the release and then change the hash method to dual.