diff --git a/net/mpifx/Makefile b/net/mpifx/Makefile
index b49ce4325cb3..338f8a3bde47 100644
--- a/net/mpifx/Makefile
+++ b/net/mpifx/Makefile
@@ -1,39 +1,36 @@
 PORTNAME=	mpifx
-DISTVERSION=	1.5
-PORTREVISION=	1
+DISTVERSION=	1.6
 CATEGORIES=	net devel
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Modern Fortran wrappers around MPI routines
 WWW=		https://github.com/dftbplus/mpifx
 
 LICENSE=	BSD2CLAUSE
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
 BUILD_DEPENDS=	fypp:devel/py-fypp@${PY_FLAVOR}
 
 USES=		cmake:testing fortran mpi:mpich python:build
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	dftbplus
 
 CMAKE_ON=	BUILD_SHARED_LIBS
 
 post-patch:
 	${REINPLACE_CMD} -e '/include(CTest)/d' ${WRKSRC}/CMakeLists.txt
 
-post-test: # run test programs # at least one test crashes, see https://github.com/dftbplus/mpifx/issues/35
+post-test: # run test programs without mpirun (CTest disabled, see https://github.com/dftbplus/mpifx/issues/49)
 .for f in test_allgather test_allgatherv test_allreduce test_bcast test_comm_split test_gather test_gatherv test_reduce test_scatter test_scatterv
 	cd ${BUILD_WRKSRC}/test && ./${f}
 .endfor
 
 .include <bsd.port.pre.mk>
 
 .if ${FORTRAN_DEFAULT} == gfortran && ${GCC_DEFAULT} >= 10
 # workaround for Type mismatch in argument 'cc' at (1); passed COMPLEX(8) to REAL(8)
 FFLAGS+=	-fallow-argument-mismatch
 .endif
 
-# tests fail to run: https://github.com/dftbplus/mpifx/issues/49
-
 .include <bsd.port.post.mk>
diff --git a/net/mpifx/distinfo b/net/mpifx/distinfo
index c69546ded5ef..ae9cbf0079bb 100644
--- a/net/mpifx/distinfo
+++ b/net/mpifx/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1710350639
-SHA256 (dftbplus-mpifx-1.5_GH0.tar.gz) = 3801cbd6134b30f403b59346b40ff5bfb47ebe125892cf483e78b477c20b1b02
-SIZE (dftbplus-mpifx-1.5_GH0.tar.gz) = 62405
+TIMESTAMP = 1778683451
+SHA256 (dftbplus-mpifx-1.6_GH0.tar.gz) = 5ec9bcb7b4d943109dddda2bec7ae29b82b9d5653566543ee451e75c76c8c3e1
+SIZE (dftbplus-mpifx-1.6_GH0.tar.gz) = 63414
diff --git a/net/mpifx/files/patch-test_test__comm__split.f90 b/net/mpifx/files/patch-test_test__comm__split.f90
new file mode 100644
index 000000000000..52b1d6036683
--- /dev/null
+++ b/net/mpifx/files/patch-test_test__comm__split.f90
@@ -0,0 +1,16 @@
+-- Fix division by zero (SIGFPE) when running with a single MPI process.
+-- With size=1, groupsize = 1/2 = 0 causes an integer divide-by-zero in the
+-- next line. Use max(1, ...) to guard against that.
+-- https://github.com/dftbplus/mpifx/issues/35
+
+--- test/test_comm_split.f90.orig	2026-05-13 15:13:45 UTC
++++ test/test_comm_split.f90
+@@ -7,7 +7,7 @@ program test_comm_split
+ 
+   call mpifx_init()
+   call allproc%init()
+-  groupsize = allproc%size / 2
++  groupsize = max(1, allproc%size / 2)
+   mygroup = allproc%rank / groupsize
+   call allproc%split(mygroup, allproc%rank, groupproc)
+   write(*, "(3(A,1X,I0,1X))") "GLOBAL ID:", allproc%rank, "SUBGROUP", &