Compile Error In IMAP Email Module

I am moving an app from 6.10.9 to 7.6.0.  The app compiles and runs successfully in 6.10.9.  However, I receive the following error when trying to start up in 7.6.0:

Buildfile: C:\Users\mkump\Documents\Mendix\PITHOS-main\deployment\build_core.xml

compile:
    [javac] Compiling 2 source files to C:\Users\mkump\Documents\Mendix\PITHOS-main\deployment\run\bin
    [javac] C:\Users\mkump\Documents\Mendix\PITHOS-main\javasource\imap_pop3_email\actions\EmailHandler.java:423: error: incompatible types: int cannot be converted to Long
    [javac] 				attach.setSize(bodyPart.getSize());
    [javac] 				                               ^
    [javac] Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output
    [javac] 1 error

The IMAP_POP3 module has been updated to the most recent version (3.1).

As my Java skills are minimal, any pointers would be appreciated.

Thanks in advance.