diff --git a/config/gfortran.cfg b/config/gfortran.cfg
index 33ce48ba..41181c32 100644
--- a/config/gfortran.cfg
+++ b/config/gfortran.cfg
@@ -10,7 +10,7 @@
 #
 #
 [COMMON]
-FC           : gfortran -g -ffree-line-length-none -I . -fPIC -march=native
+FC           : gfortran -g -ffree-line-length-none -I . -fPIC -march=native -std=legacy
 LAPACK_LIB   : -lblas -llapack
 IRPF90       : irpf90
 IRPF90_FLAGS : --ninja --align=32 --assert -DSET_NESTED
diff --git a/config/gfortran_armpl.cfg b/config/gfortran_armpl.cfg
index fb5ee1cc..db0904e2 100644
--- a/config/gfortran_armpl.cfg
+++ b/config/gfortran_armpl.cfg
@@ -13,7 +13,7 @@
 #
 #
 [COMMON]
-FC           : gfortran -g -ffree-line-length-none -I . -fPIC -march=native
+FC           : gfortran -g -ffree-line-length-none -I . -fPIC -march=native -std=legacy
 LAPACK_LIB   : -larmpl_lp64
 IRPF90       : irpf90
 IRPF90_FLAGS : --ninja --align=32 --assert -DSET_NESTED
diff --git a/config/gfortran_avx.cfg b/config/gfortran_avx.cfg
index 747dff67..5b51c640 100644
--- a/config/gfortran_avx.cfg
+++ b/config/gfortran_avx.cfg
@@ -10,7 +10,7 @@
 #
 #
 [COMMON]
-FC           : gfortran -ffree-line-length-none -I . -mavx -g -fPIC
+FC           : gfortran -ffree-line-length-none -I . -mavx -g -fPIC -std=legacy
 LAPACK_LIB   : -llapack -lblas
 IRPF90       : irpf90
 IRPF90_FLAGS : --ninja --align=32 -DSET_NESTED
diff --git a/config/gfortran_debug.cfg b/config/gfortran_debug.cfg
index 51e5a500..f903142a 100644
--- a/config/gfortran_debug.cfg
+++ b/config/gfortran_debug.cfg
@@ -10,7 +10,7 @@
 #
 #
 [COMMON]
-FC           : gfortran -g -ffree-line-length-none -I . -fPIC
+FC           : gfortran -g -ffree-line-length-none -I . -fPIC -std=legacy
 LAPACK_LIB   : -lblas -llapack
 IRPF90       : irpf90
 IRPF90_FLAGS : --ninja --align=32 --assert -DSET_NESTED
diff --git a/config/gfortran_mpi.cfg b/config/gfortran_mpi.cfg
index 1af3ca45..7cc88f1f 100644
--- a/config/gfortran_mpi.cfg
+++ b/config/gfortran_mpi.cfg
@@ -10,7 +10,7 @@
 #
 #
 [COMMON]
-FC           : mpif90 -ffree-line-length-none -I . -g -fPIC
+FC           : mpif90 -ffree-line-length-none -I . -g -fPIC -std=legacy
 LAPACK_LIB   :  -lblas -llapack
 IRPF90       : irpf90
 IRPF90_FLAGS : --ninja --align=32 -DMPI -DSET_NESTED
diff --git a/config/gfortran_openblas.cfg b/config/gfortran_openblas.cfg
index ab67d8c3..5db46fce 100644
--- a/config/gfortran_openblas.cfg
+++ b/config/gfortran_openblas.cfg
@@ -10,7 +10,7 @@
 #
 #
 [COMMON]
-FC           : gfortran -g -ffree-line-length-none -I . -fPIC -march=native
+FC           : gfortran -g -ffree-line-length-none -I . -fPIC -march=native -std=legacy
 LAPACK_LIB   : -lopenblas
 IRPF90       : irpf90
 IRPF90_FLAGS : --ninja --align=32 --assert -DSET_NESTED