Index: Makefile
===================================================================
--- Makefile
+++ Makefile
@@ -2,6 +2,7 @@
 
 PORTNAME=	opentracker
 PORTVERSION=	0.2017.08.13
+PORTREVISION=	1
 CATEGORIES=	net
 MASTER_SITES=	http://www.bayofrum.net/dist/${PORTNAME}/ \
 
@@ -13,7 +14,12 @@
 USES=		tar:bzip2
 USE_RC_SUBR=	${PORTNAME}
 
-OPTIONS_DEFINE= COMPRESSION_GZIP DEBUG_HTTPERROR FULLSCRAPE RESTRICT_STATS IPV6
+FLAVORS=	ipv4 ipv6
+ipv6_PKGNAMESUFFIX=	-ipv6
+ipv4_CONFLICTS=	${PORTNAME}-ipv6
+ipv6_CONFLICTS=	${PORTNAME}
+
+OPTIONS_DEFINE= COMPRESSION_GZIP DEBUG_HTTPERROR FULLSCRAPE RESTRICT_STATS
 OPTIONS_SINGLE=	ACCESSLIST
 OPTIONS_SINGLE_ACCESSLIST=	ACCESSLIST_OPEN ACCESSLIST_BLACK \
 				ACCESSLIST_WHITE
@@ -48,12 +54,12 @@
 FEATURES+=-DWANT_FULLSCRAPE
 .endif
 
-.if ${PORT_OPTIONS:MIPV6}
-FEATURES+=-DWANT_V6
-.endif
-
 .if ${PORT_OPTIONS:MRESTRICT_STATS}
 FEATURES+=-DWANT_RESTRICT_STATS
+.endif
+
+.if ${FLAVOR:U} == ipv6
+FEATURES+=-DWANT_V6
 .endif
 
 MAKE_ENV+=FEATURES="${FEATURES}"