I decided to post this article since I am hearing quite often about developers using Disk and GAC for registering the custom plugin assemblies in CRM 2011/2013/2015/2016. I have also heard claims such as “you must register on disk in order to debug” or “it is easier to update the assembly version when they are stored on disk” which I will do my best to disprove.
1. Only database assemblies can be packaged in solutions
2. Zero service interruption to update a database assembly
3. Simplified organization backup / import.
4. Disk assemblies will not support multiple versions
Because both versions of the assemblies would have the same file name then you cannot register them simultaneously on disk.