diff --git a/appveyor.yml b/appveyor.yml
index 3612f6882..d2bdab84e 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -51,12 +51,15 @@ cache:
 - jom_1_1_3.zip
 - sip-4.19.8.zip
 - C:\R
+- c:\tools\vcpkg\installed\
 - qwt
 
 install:
 # Get the libraries
 - if not exist gc-ci-libs.zip appveyor DownloadFile "https://github.com/GoldenCheetah/WindowsSDK/releases/download/v0.1.1/gc-ci-libs.zip"
 - 7z x -y gc-ci-libs.zip -oC:\libs
+# GSL
+- vcpkg install gsl:x64-windows
 
 # Get config
 - copy qwt\qwtconfig.pri.in qwt\qwtconfig.pri
@@ -93,6 +96,11 @@ install:
 - echo PYTHONINCLUDES=-ICore -I\"c:\python37-x64\include\" >> src\gcconfig.pri
 - echo PYTHONLIBS=-L\"c:\python37-x64\libs\" -lpython37 >> src\gcconfig.pri
 
+# GSL
+- echo DEFINES+=GC_WANT_GSL >> src\gcconfig.pri
+- echo GSL_INCLUDES=c:\tools\vcpkg\installed\x64-windows\include >> src\gcconfig.pri
+- echo GSL_LIBS=-Lc:\tools\vcpkg\installed\x64-windows\lib -lgsl -lgslcblas >> src\gcconfig.pri
+
 before_build:
 # Define GC version string, only for tagged builds
 - if %APPVEYOR_REPO_TAG% == "true" (echo DEFINES+=GC_VERSION=VERSION_STRING >> src/gcconfig.pri)
@@ -144,6 +152,7 @@ after_build:
 - copy c:\OpenSSL-v111-Win64\license.txt "OpenSSL License.txt"
 - copy c:\python37-x64\python37.dll
 - copy c:\python37-x64\LICENSE.txt "PYTHON LICENSE.txt"
+- copy c:\tools\vcpkg\installed\x64-windows\bin\gsl*.dll
 
 # ReadMe, license and icon files
 - copy ..\Resources\win32\ReadMe.txt
@@ -158,7 +167,8 @@ after_build:
 # Build the installer
 - makensis GC3.6-Dev-Master-W64-QT5.14.2.nsi
 - move GoldenCheetah_v3.6-DEV_64bit_Windows.exe ..\..\GoldenCheetah_v3.6-DEV_x64.exe
-- ps: if ($env:APPVEYOR_REPO_COMMIT_MESSAGE_EXTENDED -Like "*[publish binaries]*") { Set-AppveyorBuildVariable -Name 'PUBLISH_BINARIES' -Value 'true' }
+- ps: Set-AppveyorBuildVariable -Name 'PUBLISH_BINARIES' -Value false
+- ps: if ($env:APPVEYOR_REPO_COMMIT_MESSAGE_EXTENDED -Like "*[publish binaries]*") { Set-AppveyorBuildVariable -Name 'PUBLISH_BINARIES' -Value true }
 
 test_script:
 # minimum test
@@ -184,3 +194,4 @@ deploy:
     artifact: GCinstaller
     on:
       PUBLISH_BINARIES: true
+      APPVEYOR_REPO_NAME: "GoldenCheetah/GoldenCheetah"
diff --git a/src/Resources/win32/GC3.6-Dev-Master-W64-QT5.14.2.nsi b/src/Resources/win32/GC3.6-Dev-Master-W64-QT5.14.2.nsi
index c413f7cac..61e5662b6 100644
--- a/src/Resources/win32/GC3.6-Dev-Master-W64-QT5.14.2.nsi
+++ b/src/Resources/win32/GC3.6-Dev-Master-W64-QT5.14.2.nsi
@@ -488,6 +488,8 @@ Section "Golden Cheetah (required)" Sec1
   SetOutPath "$INSTDIR"
   File "PYTHON LICENSE.txt"
   File "python37.dll"
+  File "gsl.dll"
+  File "gslcblas.dll"
   SetOutPath "$INSTDIR"
   File "Qt5Bluetooth.dll"
   File "Qt5Charts.dll"
@@ -1018,6 +1020,8 @@ Section Uninstall
   Delete "$INSTDIR\printsupport\windowsprintersupport.dll"
   Delete "$INSTDIR\PYTHON LICENSE.txt"
   Delete "$INSTDIR\python37.dll"
+  Delete "$INSTDIR\gsl.dll"
+  Delete "$INSTDIR\gslcblas.dll"
   Delete "$INSTDIR\Qt5Bluetooth.dll"
   Delete "$INSTDIR\Qt5Charts.dll"
   Delete "$INSTDIR\Qt5Concurrent.dll"
diff --git a/src/gcconfig.pri.in b/src/gcconfig.pri.in
index c3a1b7219..cfa4d2dcb 100644
--- a/src/gcconfig.pri.in
+++ b/src/gcconfig.pri.in
@@ -49,7 +49,7 @@
 # Windows - edit to your install location
 # us vcpkg install gsl
 #DEFINES += GC_WANT_GSL
-#GCL_INCLUDES = C:/gsl-1.11/include/
+#GSL_INCLUDES = C:/gsl-1.11/include/
 #GSL_LIBS = -LC:/gsl-1.11/bin -llibgsl-0 -llibgslcblas-0
 
 # put output into a separate dir
diff --git a/travis/linux/before_install.sh b/travis/linux/before_install.sh
index 808792049..746c90859 100755
--- a/travis/linux/before_install.sh
+++ b/travis/linux/before_install.sh
@@ -63,6 +63,9 @@ make
 sudo make install
 cd ${TRAVIS_BUILD_DIR}
 
+# GSL
+sudo apt-get -qq install libgsl-dev
+
 # AWS S3 client to upload binaries
 curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip"
 unzip awscliv2.zip
diff --git a/travis/linux/before_script.sh b/travis/linux/before_script.sh
index 1706e27be..080106fda 100755
--- a/travis/linux/before_script.sh
+++ b/travis/linux/before_script.sh
@@ -46,6 +46,9 @@ sed -i "s|#\(SRMIO_INSTALL =.*\)|\1 /usr/local|" src/gcconfig.pri
 echo DEFINES += GC_WANT_PYTHON >> src/gcconfig.pri
 echo PYTHONINCLUDES = -I/usr/include/python3.7 >> src/gcconfig.pri
 echo PYTHONLIBS = -L/usr/lib/python3.7/config-3.7m-x86_64-linux-gnu -lpython3.7m >> src/gcconfig.pri
+# GSL
+echo DEFINES += GC_WANT_GSL >> src/gcconfig.pri
+echo GSL_LIBS = -lgsl -lgslcblas -lm >> src/gcconfig.pri
 
 # Patch Secrets.h
 sed -i "s/__GC_GOOGLE_CALENDAR_CLIENT_SECRET__/"$GC_GOOGLE_CALENDAR_CLIENT_SECRET"/" src/Core/Secrets.h
diff --git a/travis/osx/before_install.sh b/travis/osx/before_install.sh
index 1de3413d8..070b28bcc 100755
--- a/travis/osx/before_install.sh
+++ b/travis/osx/before_install.sh
@@ -7,6 +7,7 @@ brew update
 brew unlink python@2 # to avoid conflicts with qt/libical dependence on python
 brew upgrade python3 # to get 3.7.7
 brew upgrade qt5 # to get 5.14.2
+brew install gsl
 brew install libical
 brew upgrade libusb
 brew install srmio
diff --git a/travis/osx/before_script.sh b/travis/osx/before_script.sh
index 90f63aa53..d86bb375c 100755
--- a/travis/osx/before_script.sh
+++ b/travis/osx/before_script.sh
@@ -55,6 +55,9 @@ echo "QMAKE_CFLAGS_RELEASE += -mmacosx-version-min=10.7 -arch x86_64" >> src/gcc
 echo DEFINES += GC_WANT_PYTHON >> src/gcconfig.pri
 echo PYTHONINCLUDES = -ICore `python3-config --includes` >> src/gcconfig.pri
 echo PYTHONLIBS = `python3-config --ldflags` >> src/gcconfig.pri
+# GSL
+echo DEFINES += GC_WANT_GSL >> src/gcconfig.pri
+echo GSL_LIBS = -lgsl -lgslcblas -lm >> src/gcconfig.pri
 
 # Patch Secrets.h
 sed -i "" "s/__GC_GOOGLE_CALENDAR_CLIENT_SECRET__/"$GC_GOOGLE_CALENDAR_CLIENT_SECRET"/" src/Core/Secrets.h
diff --git a/travis/osx/script.sh b/travis/osx/script.sh
index 52b5d40e7..49b2ec620 100755
--- a/travis/osx/script.sh
+++ b/travis/osx/script.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 set -ev
-CC=clang CXX=clang++ /usr/local/opt/qt5/bin/qmake -makefile -recursive QMAKE_CXXFLAGS_WARN_ON+="-Wno-unused-private-field -Wno-c++11-narrowing -Wno-deprecated-declarations -Wno-deprecated-register"
+CC=clang CXX=clang++ /usr/local/opt/qt5/bin/qmake -makefile -recursive QMAKE_CXXFLAGS_WARN_ON+="-Wno-unused-private-field -Wno-c++11-narrowing -Wno-deprecated-declarations -Wno-deprecated-register -Wno-nullability-completeness"
 CC=clang CXX=clang++ make qmake_all
 CC=clang CXX=clang++ make -j4 sub-qwt --silent
 CC=clang CXX=clang++ make -j4 sub-src --silent || CC=clang CXX=clang++ make sub-src