diff --git a/.travis.yml b/.travis.yml
index 0fef3f44..ef6c24b5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,17 +10,6 @@ sudo: required
 group: edge
 
 
-###################
-# global settings #
-###################
-
-env:
-  global:
-   # The next declaration is the encrypted COVERITY_SCAN_TOKEN, created
-   #   via the "travis encrypt" command using the project repo's public key
-   - secure: "m89SSgE+ASLO38rSKx7MTXK3n5NkP9bIx95jwY71YEiuFzib30PDJ/DifKnXxBjvy/AkCGztErQRk/8ZCvq+4HXozU2knEGnL/RUitvlwbhzfh2D4lmS3BvWBGS3N3NewoPBrRmdcvnT0xjOGXxtZaJ3P74TkB9GBnlz/HmKORA="
-
-
 ################
 # build matrix #
 ################
@@ -129,6 +118,9 @@ matrix:
     env:
       - SPECIAL=coverity
       - COMPILER=clang++-3.6
+        # The next declaration is the encrypted COVERITY_SCAN_TOKEN, created
+        #   via the "travis encrypt" command using the project repo's public key
+      - secure: "m89SSgE+ASLO38rSKx7MTXK3n5NkP9bIx95jwY71YEiuFzib30PDJ/DifKnXxBjvy/AkCGztErQRk/8ZCvq+4HXozU2knEGnL/RUitvlwbhzfh2D4lmS3BvWBGS3N3NewoPBrRmdcvnT0xjOGXxtZaJ3P74TkB9GBnlz/HmKORA="
 
   # OSX / Clang
 
@@ -150,6 +142,9 @@ matrix:
   - os: osx
     osx_image: xcode11.2
 
+  - os: osx
+    osx_image: xcode12
+
   # Linux / GCC
 
   - os: linux
diff --git a/Makefile b/Makefile
index 3d296baf..b2e9b581 100644
--- a/Makefile
+++ b/Makefile
@@ -562,7 +562,7 @@ check-amalgamation:
 check-single-includes:
 	@for x in $(SRCS); do \
 	  echo "Checking self-sufficiency of $$x..." ; \
-	  echo "#include <$$x>\nint main() {}\n" | sed 's|include/||' > single_include_test.cpp; \
+	  echo "#include <$$x>\nint main() {}\n" | $(SED) 's|include/||' > single_include_test.cpp; \
 	  $(CXX) $(CXXFLAGS) -Iinclude -std=c++11 single_include_test.cpp -o single_include_test; \
 	  rm -f single_include_test.cpp single_include_test; \
 	done
@@ -572,7 +572,7 @@ check-single-includes:
 # CMake
 ##########################################################################
 
-# grep "^option" CMakeLists.txt test/CMakeLists.txt | sed 's/(/ /' | awk '{print $2}' | xargs
+# grep "^option" CMakeLists.txt test/CMakeLists.txt | $(SED) 's/(/ /' | awk '{print $2}' | xargs
 
 # check if all flags of our CMake files work
 check_cmake_flags_do:
@@ -651,6 +651,6 @@ clean:
 update_hedley:
 	rm -f include/nlohmann/thirdparty/hedley/hedley.hpp include/nlohmann/thirdparty/hedley/hedley_undef.hpp
 	curl https://raw.githubusercontent.com/nemequ/hedley/master/hedley.h -o include/nlohmann/thirdparty/hedley/hedley.hpp
-	gsed -i 's/HEDLEY_/JSON_HEDLEY_/g' include/nlohmann/thirdparty/hedley/hedley.hpp
-	grep "[[:blank:]]*#[[:blank:]]*undef" include/nlohmann/thirdparty/hedley/hedley.hpp | grep -v "__" | sort | uniq | gsed 's/ //g' | gsed 's/undef/undef /g' > include/nlohmann/thirdparty/hedley/hedley_undef.hpp
+	$(SED) -i 's/HEDLEY_/JSON_HEDLEY_/g' include/nlohmann/thirdparty/hedley/hedley.hpp
+	grep "[[:blank:]]*#[[:blank:]]*undef" include/nlohmann/thirdparty/hedley/hedley.hpp | grep -v "__" | sort | uniq | $(SED) 's/ //g' | $(SED) 's/undef/undef /g' > include/nlohmann/thirdparty/hedley/hedley_undef.hpp
 	$(MAKE) amalgamate
diff --git a/README.md b/README.md
index 744163bb..000ce1cf 100644
--- a/README.md
+++ b/README.md
@@ -1226,6 +1226,7 @@ The following compilers are currently used in continuous integration at [Travis]
 | Apple Clang 10.0.1 (clang-1001.0.46.4); Xcode 10.2.1            | macOS 10.14.4      | Travis         |
 | Apple Clang 11.0.0 (clang-1100.0.33.12); Xcode 11.2.1           | macOS 10.14.6      | Travis         |
 | Apple Clang 11.0.3 (clang-1103.0.32.59); Xcode 11.4.1           | macOS 10.15.4      | GitHub Actions |
+| Apple Clang 12.0.0 (clang-1200.0.22.7); Xcode 11.4.1            | macOS 10.15.5      | Travis         |
 | Clang 3.5.0 (3.5.0-4ubuntu2~trusty2)                            | Ubuntu 14.04.5 LTS | Travis         |
 | Clang 3.6.2 (3.6.2-svn240577-1~exp1)                            | Ubuntu 14.04.5 LTS | Travis         |
 | Clang 3.7.1 (3.7.1-svn253571-1~exp1)                            | Ubuntu 14.04.5 LTS | Travis         |