diff --git a/devel/libdsp/Makefile b/devel/libdsp/Makefile
index f1662c06cb4f..1e079fa1c689 100644
--- a/devel/libdsp/Makefile
+++ b/devel/libdsp/Makefile
@@ -1,28 +1,31 @@
 PORTNAME=	libdsp
 PORTVERSION=	5.0.2
 PORTREVISION=	3
 CATEGORIES=	devel audio
 MASTER_SITES=	SF/${PORTNAME}/${PORTNAME}-stable-src/${PORTVERSION} \
 		http://mirror.mcx2.org/
 
 DISTNAME=	${PORTNAME}-src-${PORTVERSION}
 
 MAINTAINER=	ports@FreeBSD.org
 COMMENT=	C++ class library of common digital signal processing functions
 WWW=		https://libdsp.sourceforge.net/overview.html
 
+DEPRECATED=	Abandonware, last release upstream in 2005 and unmaintained since 2015
+EXPIRATION_DATE=2024-09-30
+
 WRKSRC=		${WRKDIR}/libdsp-src-${PORTVERSION}/${PORTNAME:S/dsp/DSP/}-${PORTVERSION}
 
 MAKE_ENV=	MKDIR="${MKDIR}" INLINE_VER="${INLINE_VER}"
 MAKEFILE=	Makefile.BSD
 USES=		gmake libtool:build
 USE_LDCONFIG=	yes
 
 INLINE_VER=	1.4.0
 
 CFLAGS_i386+=	-DDSP_X86
 
 post-install:
 	${STRIP_CMD} ${STAGEDIR}${PREFIX}/lib/libdsp.so
 
 .include <bsd.port.mk>