diff --git a/science/agrum/Makefile b/science/agrum/Makefile
index 05e734198bec..fa53c8d5cf13 100644
--- a/science/agrum/Makefile
+++ b/science/agrum/Makefile
@@ -1,62 +1,64 @@
 PORTNAME=	agrum
 DISTVERSION=	1.5.2
 CATEGORIES=	science math
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Graphical modeler for Bayesian networks, influence diagrams, etc
 WWW=		https://agrum.gitlab.io/
 
 LICENSE=	GPLv3
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
+BROKEN_FreeBSD_12=	requires modern C++ compiler: error: invalid value 'c++2b'
+
 USES=		cmake compiler:c++20-lang shebangfix # the 'act' executable uses 'python' and is broken, when act is broken CMakeLists.txt builds with default configuration which is fine
 USE_LDCONFIG=	yes
 
 LLD_UNSAFE=	yes
 
 USE_GITLAB=	yes
 GL_ACCOUNT=	agrumery
 GL_PROJECT=	aGrUM
 GL_COMMIT=	9534f1a9e4855c9ec31883cb9b3acc88113a13e1
 
 SHEBANG_FILES=	act
 
 CMAKE_ARGS=	-DPython_EXECUTABLE=${PYTHON_CMD}
 CMAKE_OFF=	USE_SWIG
 
 PLIST_SUB+=	VERSION=${PORTVERSION}
 
 OPTIONS_DEFINE=		ODBC OPENMP PYTHON
 OPTIONS_DEFAULT=	OPENMP PYTHON
 OPTIONS_SUB=		yes
 
 ODBC_CMAKE_BOOL=	USE_NANODBC
 ODBC_USES=		localbase:ldflags
 ODBC_LIB_DEPENDS=	libodbc.so:databases/unixODBC
 
 OPENMP_CMAKE_BOOL=	USE_OPENMP
 
 PYTHON_CMAKE_BOOL=	BUILD_PYTHON
 PYTHON_USES=		python:3.7+
 PYTHON_PLIST_SUB=	PYTHON_VER_MAJ=${PYTHON_VER:R}
 PYTHON_RUN_DEPENDS=	${PYNUMPY} \
 			${PYTHON_PKGNAMEPREFIX}configparser>0:devel/py-configparser@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}ipython>0:devel/ipython@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}matplotlib>0:math/py-matplotlib@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}nbconvert>0:devel/py-nbconvert@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}nbformat>0:devel/py-nbformat@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}pandas>0:math/py-pandas@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}pydotplus>0:graphics/py-pydotplus@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}scipy>0:science/py-scipy@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}scikit-learn>0:science/py-scikit-learn@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}six>0:devel/py-six@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}tqdm>0:misc/py-tqdm@${PY_FLAVOR}
 			# see wrappers/pyAgrum/requirements.txt and wrappers/pyAgrum/testunits/optional_requirements.txt
 
 BINARY_ALIAS=	gcc=${CC} g++=${CXX} # only for tests, see https://gitlab.com/agrumery/aGrUM/-/issues/100
 
 do-test:
 	@cd ${WRKSRC} && \
 		${SETENV} ${MAKE_ENV} ./act test release agrum -t all
 
 .include <bsd.port.mk>