diff --git a/CMakeLists.txt b/CMakeLists.txt
index 64d98dd30..008dea9ed 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,7 +7,7 @@ project(FIMS
 ) # CXX is the language name
 
 # GoogleTest requires at least C++11
-set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
 
 include(FetchContent)
 
diff --git a/src/Makevars b/src/Makevars
index a3b36318d..0cdfd0add 100644
--- a/src/Makevars
+++ b/src/Makevars
@@ -1,4 +1,4 @@
-CXX_STD = CXX11
+CXX_STD = CXX17
 PKG_CXXFLAGS =  -DTMB_MODEL  -DTMB_EIGEN_DISABLE_WARNINGS -w
-CXX17STD = -std=c++11 -w
+CXX17STD = -std=c++17 -w
 
diff --git a/src/Makevars.win b/src/Makevars.win
index ab39ecce2..fd40404e5 100644
--- a/src/Makevars.win
+++ b/src/Makevars.win
@@ -1,6 +1,6 @@
-CXX_STD = CXX11
-PKG_CXXFLAGS =  -DTMB_MODEL  -DTMB_EIGEN_DISABLE_WARNINGS
-CXX17STD = -std=c++11
+CXX_STD = CXX17
+PKG_CXXFLAGS =  -DTMB_MODEL  -DTMB_EIGEN_DISABLE_WARNINGS -fpermissive
+CXX17STD = -std=c++17
 CXX14FLAGS = Wa, -mbig-obj -O3
 CXX17FLAGS = Wa, -mbig-obj -O3