diff --git a/app/build.gradle b/app/build.gradle
index cb50b563..dcf45acd 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -39,7 +39,7 @@ android {
             applicationVariants.all { variant ->
                 variant.outputs.all { output ->
                     def date = new Date()
-                    def formattedDate = date.format('yyMMdd:HHmm')
+                    def formattedDate = date.format('yyMMdd_HHmm')
                     def appName = "PokerAnalytics"
                     def buildType = variant.variantData.variantConfiguration.buildType.name
                     def newName