diff --git a/comms/libmodbus/Makefile b/comms/libmodbus/Makefile
index 01038c936540..180c4dddd679 100644
--- a/comms/libmodbus/Makefile
+++ b/comms/libmodbus/Makefile
@@ -1,29 +1,35 @@
 PORTNAME=	libmodbus
-PORTVERSION=	3.1.7
-PORTREVISION=	2
+DISTVERSIONPREFIX=	v
+DISTVERSION=	3.1.8
 CATEGORIES=	comms
-MASTER_SITES=	https://libmodbus.org/releases/
 
 MAINTAINER=	bofh@FreeBSD.org
 COMMENT=	Modbus library
 WWW=		https://libmodbus.org/
 
 LICENSE=	LGPL21+
 LICENSE_FILE=	${WRKSRC}/COPYING.LESSER
 
-USES=		cpe gmake libtool pathfix
+USES=		autoreconf cpe gmake libtool pathfix
+USE_GITHUB=	yes
+GH_ACCOUNT=	stephane
 USE_LDCONFIG=	yes
 
 GNU_CONFIGURE=	yes
-GNU_CONFIGURE_MANPREFIX=${PREFIX}/share
 
 INSTALL_TARGET=	install-strip
 
 OPTIONS_DEFINE=		DOCS MANPAGES
 OPTIONS_DEFAULT=	MANPAGES
 OPTIONS_SUB=		yes
 
-MANPAGES_BUILD_DEPENDS=	a2x:textproc/asciidoc \
-			xmlto:textproc/xmlto
+MANPAGES_BUILD_DEPENDS=	go-md2man:textproc/go-md2man
+
+post-install-MANPAGES-on:
+	go-md2man -in docs/index.md | gzip > ${STAGEDIR}${PREFIX}/share/man/man7/libmodbus.7.gz
+	for files in `${FIND} ${WRKSRC}/docs -type f -name 'modbus*.md'`; do \
+		basefiles=`basename $${files} .md`; \
+		go-md2man -in $${files} | gzip > ${STAGEDIR}${PREFIX}/share/man/man3/$${basefiles}.3.gz; \
+	done
 
 .include <bsd.port.mk>
diff --git a/comms/libmodbus/distinfo b/comms/libmodbus/distinfo
index ca9dab8ce3d2..3a419fbabbb9 100644
--- a/comms/libmodbus/distinfo
+++ b/comms/libmodbus/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1654519527
-SHA256 (libmodbus-3.1.7.tar.gz) = 7dfe958431d0570b271e1a5b329b76a658e89c614cf119eb5aadb725c87f8fbd
-SIZE (libmodbus-3.1.7.tar.gz) = 490162
+TIMESTAMP = 1751271066
+SHA256 (stephane-libmodbus-v3.1.8_GH0.tar.gz) = 4cabc5dc01b2faab853474c5d9db6386d04f37a476f843e239bff25480310adb
+SIZE (stephane-libmodbus-v3.1.8_GH0.tar.gz) = 201697