diff -aur ultraftp.orig/Makefile ultraftp/Makefile
--- ultraftp.orig/Makefile	2019-06-19 18:37:41.913323155 +0200
+++ ultraftp/Makefile	2019-06-19 18:37:47.759989787 +0200
@@ -3,7 +3,6 @@
 SOURCES = $(shell echo *.java)
 CLASSES = $(SOURCES:%.java=%.class)
 ARCHIVE = ultraftp.jar
-JC_ARGS = -target 1.4 -source 1.4
 
 all: $(CLASSES) $(ARCHIVE)