ProGuard says Unsupported class version number [52.0] (maximum 51.0, Java 1.7) with sbt-proguard

Question

I\'m on Mac OS X 10.9.2 and sbt 0.13.3-SNAPSHOT (built from the sources), Java 8 and sbt-proguard 0.2.2 p

Answer 1

The question is really interesting and i was facing the same problem with the only difference that i added Proguard programmatically by using maven. Consequently, i considered that it will be helpful to post my solution although it is a bit different from the main question. For all those that using maven and faces the same problem, my workaround fix was to update the version of Proguard by using it as runtime inside the plugin, so the working pom.xml looks like this

  
                    com.github.wvengen
                    proguard-maven-plugin
                    2.0.14
                    
                        
                            package
                            
                                proguard
                            
                        
                    
                    
                        true
                        true
                        false
                        true
                        ${project.build.finalName}-jar-with-dependencies.jar
                        true
                        
                            ${java.home}/lib/rt.jar
                            ${java.home}/lib/jce.jar
                            ${java.home}/lib/ext/sunjce_provider.jar
                        
                        
                        -allowaccessmodification
                        -optimizationpasses 3
                        -overloadaggressively
                        -repackageclasses ''
                        -dontusemixedcaseclassnames
                        -dontskipnonpubliclibraryclasses
                        -flattenpackagehierarch
                        -dontwarn 
                            -keep public class com.StocksNews.App {
                                public static void main(java.lang.String[]);
                                }
                            
                        
                    
                    
                        
                            net.sf.proguard
                            proguard-base
                            6.1.1
                            runtime