Java Compile error after Excel Exporter module

Hi

I have downloaded the Excel Exporte app store module for our app in 6.9

Now when I want to run the app I got this error:

compile:
    [javac] Compiling 11 source files to C:\Users\123\Documents\Mendix\MxApp\deployment\run\bin
    [javac] C:\Users\123\Documents\Mendix\MxApp\javasource\xlsreport\report\DataOQL.java:734: error: cannot find symbol
    [javac] 		return dateTime.withZone(DateTimeZone.UTC).toLocalDateTime().toDate();
    [javac] 		                                                            ^
    [javac]   symbol:   method toDate()
    [javac]   location: class LocalDateTime
    [javac] Note: C:\Users\123\Documents\Mendix\MxApp\\javasource\com\mendix\core\Core.java uses or overrides a deprecated API.
    [javac] Note: Recompile with -Xlint:deprecation for details.
    [javac] Note: C:\Users\123\Documents\Mendix\MxApp\javasource\com\mendix\core\Core.java uses unchecked or unsafe operations.
    [javac] Note: Recompile with -Xlint:unchecked for details.
    [javac] 1 error

Obviously it has to do that the Excel exporter modules "uses/orverrides a deprecated api".

The question now is how to solve this java stuff?