diff --git a/appveyor.yml b/appveyor.yml
index 65aa4b17..b909df23 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -6,124 +6,79 @@ environment:
     # SDK v7.0 MSVC Express 2008's SetEnv.cmd script will fail if the
     # /E:ON and /V:ON options are not enabled in the batch script intepreter
     # See: http://stackoverflow.com/a/13751649/163740
-    CMD_IN_ENV: "cmd /E:ON /V:ON /C %APPVEYOR_BUILD_FOLDER%\\ci\\appveyor\\run_with_env.cmd"
     TRUE_MM_BUILD_DIR: "%APPVEYOR_BUILD_FOLDER%\\minorminer\\dist"
     DEBUG_MM_BUILD_DIR: "%APPVEYOR_BUILD_FOLDER%\\minorminer\\debug_dist"
 
   # PyPI login
-  username: dwtools
-  password:
+  TWINE_USERNAME: dwtools
+  TWINE_PASSWORD:
     secure: 9/YAQhmz9Kb1ZeXzhBYeQA==
 
   matrix:
     - PYTHON: "C:\\Python35"
-      PYTHON_VERSION: "3.5.x"
-      PYTHON_ARCH: "32"
       CPPDEBUG: 1
 
     - PYTHON: "C:\\Python35-x64"
-      PYTHON_VERSION: "3.5.x"
-      PYTHON_ARCH: "64"
       CPPDEBUG: 1
 
     - PYTHON: "C:\\Python36"
-      PYTHON_VERSION: "3.6.x"
-      PYTHON_ARCH: "32"
       CPPDEBUG: 1
 
     - PYTHON: "C:\\Python36-x64"
-      PYTHON_VERSION: "3.6.x"
-      PYTHON_ARCH: "64"
       CPPDEBUG: 1
 
-    - PYTHON: "C:\\Python35"
-      PYTHON_VERSION: "3.5.x"
-      PYTHON_ARCH: "32"
+    - PYTHON: "C:\\Python37"
+      CPPDEBUG: 1
 
-    - PYTHON: "C:\\Python35-x64"
-      PYTHON_VERSION: "3.5.x"
-      PYTHON_ARCH: "64"
+    - PYTHON: "C:\\Python37-x64"
+      CPPDEBUG: 1
 
-    - PYTHON: "C:\\Python36"
-      PYTHON_VERSION: "3.6.x"
-      PYTHON_ARCH: "32"
+    - PYTHON: "C:\\Python38"
+      CPPDEBUG: 1
 
-    - PYTHON: "C:\\Python36-x64"
-      PYTHON_VERSION: "3.6.x"
-      PYTHON_ARCH: "64"
+    - PYTHON: "C:\\Python38-x64"
+      CPPDEBUG: 1
 
+    - PYTHON: "C:\\Python35"
+    - PYTHON: "C:\\Python35-x64"
+    - PYTHON: "C:\\Python36"
+    - PYTHON: "C:\\Python36-x64"
     - PYTHON: "C:\\Python37"
-      PYTHON_VERSION: "3.7.x"
-      PYTHON_ARCH: "32"
-
     - PYTHON: "C:\\Python37-x64"
-      PYTHON_VERSION: "3.7.x"
-      PYTHON_ARCH: "64"
+    - PYTHON: "C:\\Python38"
+    - PYTHON: "C:\\Python38-x64"
 
 install:
-  # If there is a newer build queued for the same PR, cancel this one.
-  # The AppVeyor 'rollout builds' option is supposed to serve the same
-  # purpose but it is problematic because it tends to cancel builds pushed
-  # directly to master instead of just PR builds (or the converse).
-  # credits: JuliaLang developers.
-  - ps: if ($env:APPVEYOR_PULL_REQUEST_NUMBER -and $env:APPVEYOR_BUILD_NUMBER -ne ((Invoke-RestMethod `
-        https://ci.appveyor.com/api/projects/$env:APPVEYOR_ACCOUNT_NAME/$env:APPVEYOR_PROJECT_SLUG/history?recordsNumber=50).builds | `
-        Where-Object pullRequestId -eq $env:APPVEYOR_PULL_REQUEST_NUMBER)[0].buildNumber) { `
-          throw "There are newer queued builds for this pull request, failing early." }
-  - ECHO "Filesystem root:"
-  - ps: "ls \"C:/\""
-
-  - ECHO "Installed SDKs:"
-  - ps: "ls \"C:/Program Files/Microsoft SDKs/Windows\""
-
-  # Install Python (from the official .msi of http://python.org) and pip when
-  # not already installed.
-  - ps: if (-not(Test-Path($env:PYTHON))) { & ci\appveyor\install.ps1 }
-
-  # Prepend newly installed Python to the PATH of this build (this cannot be
-  # done from inside the powershell script as it would require to restart
-  # the parent CMD process).
-  - "SET PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%"
 
-  # Check that we have the expected version and architecture for Python
-  - "python --version"
-  - "python -c \"import struct; print(struct.calcsize('P') * 8)\""
+  # required to link py35 (x86 and x64)
+  - set PATH=%PATH%;C:\Program Files (x86)\Windows Kits\8.1\bin\x86
 
-  # Upgrade to the latest version of pip to avoid it displaying warnings
-  # about it being out of date.
-  # - "pip install --disable-pip-version-check --user --upgrade pip"
+  # Check that we have the expected version and architecture for Python
+  - "%PYTHON%\\python.exe --version"
+  - "%PYTHON%\\python.exe -c \"import struct; print(struct.calcsize('P') * 8)\""
 
-  # Install the build dependencies of the project. If some dependencies contain
-  # compiled extensions and are not provided as pre-built wheel packages,
-  # pip will build them from source using the MSVC compiler matching the
-  # target Python version and architecture
+  # Install dependencies
   - if "%CPPDEBUG%" == "1" ( SET MM_BUILD_DIR=%DEBUG_MM_BUILD_DIR% ) else ( SET MM_BUILD_DIR=%TRUE_MM_BUILD_DIR%)
-  - "%CMD_IN_ENV% pip install cython==0.28.4"
-  - "%CMD_IN_ENV% pip install wheel setuptools --upgrade --force"
-
-
+  - "%PYTHON%\\python.exe -m pip install -r requirements.txt -r tests\\requirements.txt"
+  - "%PYTHON%\\python.exe -m pip install cython==0.28.4"
+  - "%PYTHON%\\python.exe -m pip install -U wheel setuptools twine"
+ 
 build_script:
   # Build the compiled extension
-  - "%CMD_IN_ENV% python setup.py bdist_wheel -d %MM_BUILD_DIR%"
-  - "dir %MM_BUILD_DIR%"
-  - python setup.py build_ext --inplace
+  - "%PYTHON%\\python.exe setup.py build_ext --inplace"
 
 test_script:
   # Run the project tests
-  - pip install -r requirements.txt -r tests\requirements.txt
-  - python -m nose . --exe
+  - "%PYTHON%\\python.exe -m nose . --exe"
 
 after_test:
   # If tests are successful, create binary packages for the project.
-  - "ls %MM_BUILD_DIR%"
+  - "%PYTHON%\\python.exe setup.py bdist_wheel -d %MM_BUILD_DIR%"
+  - "dir %MM_BUILD_DIR%"
 
 artifacts:
   # Archive the generated packages in the ci.appveyor.com build report.
   - path: "minorminer\\dist"
 
 deploy_script:
-  - "echo [pypi] > %USERPROFILE%\\.pypirc"
-  - "echo username: %username% >> %USERPROFILE%\\.pypirc"
-  - "echo password: %password% >> %USERPROFILE%\\.pypirc"
-  - "%CMD_IN_ENV% pip install twine"
   - cmd: "if [%APPVEYOR_REPO_TAG%]==[true] if NOT [%CPPDEBUG%]==[1] twine upload --skip-existing minorminer\\dist\\*.whl"
diff --git a/ci/appveyor/install.ps1 b/ci/appveyor/install.ps1
deleted file mode 100644
index 160ba55c..00000000
--- a/ci/appveyor/install.ps1
+++ /dev/null
@@ -1,229 +0,0 @@
-# Sample script to install Python and pip under Windows
-# Authors: Olivier Grisel, Jonathan Helmus, Kyle Kastner, and Alex Willmer
-# License: CC0 1.0 Universal: http://creativecommons.org/publicdomain/zero/1.0/
-
-$MINICONDA_URL = "http://repo.continuum.io/miniconda/"
-$BASE_URL = "https://www.python.org/ftp/python/"
-$GET_PIP_URL = "https://bootstrap.pypa.io/get-pip.py"
-$GET_PIP_PATH = "C:\get-pip.py"
-
-$PYTHON_PRERELEASE_REGEX = @"
-(?x)
-(?<major>\d+)
-\.
-(?<minor>\d+)
-\.
-(?<micro>\d+)
-(?<prerelease>[a-z]{1,2}\d+)
-"@
-
-
-function Download ($filename, $url) {
-    $webclient = New-Object System.Net.WebClient
-
-    $basedir = $pwd.Path + "\"
-    $filepath = $basedir + $filename
-    if (Test-Path $filename) {
-        Write-Host "Reusing" $filepath
-        return $filepath
-    }
-
-    # Download and retry up to 3 times in case of network transient errors.
-    Write-Host "Downloading" $filename "from" $url
-    $retry_attempts = 2
-    for ($i = 0; $i -lt $retry_attempts; $i++) {
-        try {
-            $webclient.DownloadFile($url, $filepath)
-            break
-        }
-        Catch [Exception]{
-            Start-Sleep 1
-        }
-    }
-    if (Test-Path $filepath) {
-        Write-Host "File saved at" $filepath
-    } else {
-        # Retry once to get the error message if any at the last try
-        $webclient.DownloadFile($url, $filepath)
-    }
-    return $filepath
-}
-
-
-function ParsePythonVersion ($python_version) {
-    if ($python_version -match $PYTHON_PRERELEASE_REGEX) {
-        return ([int]$matches.major, [int]$matches.minor, [int]$matches.micro,
-                $matches.prerelease)
-    }
-    $version_obj = [version]$python_version
-    return ($version_obj.major, $version_obj.minor, $version_obj.build, "")
-}
-
-
-function DownloadPython ($python_version, $platform_suffix) {
-    $major, $minor, $micro, $prerelease = ParsePythonVersion $python_version
-
-    if (($major -le 2 -and $micro -eq 0) `
-        -or ($major -eq 3 -and $minor -le 2 -and $micro -eq 0) `
-        ) {
-        $dir = "$major.$minor"
-        $python_version = "$major.$minor$prerelease"
-    } else {
-        $dir = "$major.$minor.$micro"
-    }
-
-    if ($prerelease) {
-        if (($major -le 2) `
-            -or ($major -eq 3 -and $minor -eq 1) `
-            -or ($major -eq 3 -and $minor -eq 2) `
-            -or ($major -eq 3 -and $minor -eq 3) `
-            ) {
-            $dir = "$dir/prev"
-        }
-    }
-
-    if (($major -le 2) -or ($major -le 3 -and $minor -le 4)) {
-        $ext = "msi"
-        if ($platform_suffix) {
-            $platform_suffix = ".$platform_suffix"
-        }
-    } else {
-        $ext = "exe"
-        if ($platform_suffix) {
-            $platform_suffix = "-$platform_suffix"
-        }
-    }
-
-    $filename = "python-$python_version$platform_suffix.$ext"
-    $url = "$BASE_URL$dir/$filename"
-    $filepath = Download $filename $url
-    return $filepath
-}
-
-
-function InstallPython ($python_version, $architecture, $python_home) {
-    Write-Host "Installing Python" $python_version "for" $architecture "bit architecture to" $python_home
-    if (Test-Path $python_home) {
-        Write-Host $python_home "already exists, skipping."
-        return $false
-    }
-    if ($architecture -eq "32") {
-        $platform_suffix = ""
-    } else {
-        $platform_suffix = "amd64"
-    }
-    $installer_path = DownloadPython $python_version $platform_suffix
-    $installer_ext = [System.IO.Path]::GetExtension($installer_path)
-    Write-Host "Installing $installer_path to $python_home"
-    $install_log = $python_home + ".log"
-    if ($installer_ext -eq '.msi') {
-        InstallPythonMSI $installer_path $python_home $install_log
-    } else {
-        InstallPythonEXE $installer_path $python_home $install_log
-    }
-    if (Test-Path $python_home) {
-        Write-Host "Python $python_version ($architecture) installation complete"
-    } else {
-        Write-Host "Failed to install Python in $python_home"
-        Get-Content -Path $install_log
-        Exit 1
-    }
-}
-
-
-function InstallPythonEXE ($exepath, $python_home, $install_log) {
-    $install_args = "/quiet InstallAllUsers=1 TargetDir=$python_home"
-    RunCommand $exepath $install_args
-}
-
-
-function InstallPythonMSI ($msipath, $python_home, $install_log) {
-    $install_args = "/qn /log $install_log /i $msipath TARGETDIR=$python_home"
-    $uninstall_args = "/qn /x $msipath"
-    RunCommand "msiexec.exe" $install_args
-    if (-not(Test-Path $python_home)) {
-        Write-Host "Python seems to be installed else-where, reinstalling."
-        RunCommand "msiexec.exe" $uninstall_args
-        RunCommand "msiexec.exe" $install_args
-    }
-}
-
-function RunCommand ($command, $command_args) {
-    Write-Host $command $command_args
-    Start-Process -FilePath $command -ArgumentList $command_args -Wait -Passthru
-}
-
-
-function InstallPip ($python_home) {
-    $pip_path = $python_home + "\Scripts\pip.exe"
-    $python_path = $python_home + "\python.exe"
-    if (-not(Test-Path $pip_path)) {
-        Write-Host "Installing pip..."
-        $webclient = New-Object System.Net.WebClient
-        $webclient.DownloadFile($GET_PIP_URL, $GET_PIP_PATH)
-        Write-Host "Executing:" $python_path $GET_PIP_PATH
-        & $python_path $GET_PIP_PATH
-    } else {
-        Write-Host "pip already installed."
-    }
-}
-
-
-function DownloadMiniconda ($python_version, $platform_suffix) {
-    if ($python_version -eq "3.4") {
-        $filename = "Miniconda3-3.5.5-Windows-" + $platform_suffix + ".exe"
-    } else {
-        $filename = "Miniconda-3.5.5-Windows-" + $platform_suffix + ".exe"
-    }
-    $url = $MINICONDA_URL + $filename
-    $filepath = Download $filename $url
-    return $filepath
-}
-
-
-function InstallMiniconda ($python_version, $architecture, $python_home) {
-    Write-Host "Installing Python" $python_version "for" $architecture "bit architecture to" $python_home
-    if (Test-Path $python_home) {
-        Write-Host $python_home "already exists, skipping."
-        return $false
-    }
-    if ($architecture -eq "32") {
-        $platform_suffix = "x86"
-    } else {
-        $platform_suffix = "x86_64"
-    }
-    $filepath = DownloadMiniconda $python_version $platform_suffix
-    Write-Host "Installing" $filepath "to" $python_home
-    $install_log = $python_home + ".log"
-    $args = "/S /D=$python_home"
-    Write-Host $filepath $args
-    Start-Process -FilePath $filepath -ArgumentList $args -Wait -Passthru
-    if (Test-Path $python_home) {
-        Write-Host "Python $python_version ($architecture) installation complete"
-    } else {
-        Write-Host "Failed to install Python in $python_home"
-        Get-Content -Path $install_log
-        Exit 1
-    }
-}
-
-
-function InstallMinicondaPip ($python_home) {
-    $pip_path = $python_home + "\Scripts\pip.exe"
-    $conda_path = $python_home + "\Scripts\conda.exe"
-    if (-not(Test-Path $pip_path)) {
-        Write-Host "Installing pip..."
-        $args = "install --yes pip"
-        Write-Host $conda_path $args
-        Start-Process -FilePath "$conda_path" -ArgumentList $args -Wait -Passthru
-    } else {
-        Write-Host "pip already installed."
-    }
-}
-
-function main () {
-    InstallPython $env:PYTHON_VERSION $env:PYTHON_ARCH $env:PYTHON
-    InstallPip $env:PYTHON
-}
-
-main
diff --git a/ci/appveyor/run_with_env.cmd b/ci/appveyor/run_with_env.cmd
deleted file mode 100644
index b833f7ec..00000000
--- a/ci/appveyor/run_with_env.cmd
+++ /dev/null
@@ -1,92 +0,0 @@
-:: To build extensions for 64 bit Python 3, we need to configure environment
-:: variables to use the MSVC 2010 C++ compilers from GRMSDKX_EN_DVD.iso of:
-:: MS Windows SDK for Windows 7 and .NET Framework 4 (SDK v7.1)
-::
-:: To build extensions for 64 bit Python 2, we need to configure environment
-:: variables to use the MSVC 2008 C++ compilers from GRMSDKX_EN_DVD.iso of:
-:: MS Windows SDK for Windows 7 and .NET Framework 3.5 (SDK v7.0)
-::
-:: 32 bit builds, and 64-bit builds for 3.5 and beyond, do not require specific
-:: environment configurations.
-::
-:: Note: this script needs to be run with the /E:ON and /V:ON flags for the
-:: cmd interpreter, at least for (SDK v7.0)
-::
-:: More details at:
-:: https://github.com/cython/cython/wiki/64BitCythonExtensionsOnWindows
-:: http://stackoverflow.com/a/13751649/163740
-::
-:: Author: Olivier Grisel
-:: License: CC0 1.0 Universal: http://creativecommons.org/publicdomain/zero/1.0/
-::
-:: Notes about batch files for Python people:
-::
-:: Quotes in values are literally part of the values:
-::      SET FOO="bar"
-:: FOO is now five characters long: " b a r "
-:: If you don't want quotes, don't include them on the right-hand side.
-::
-:: The CALL lines at the end of this file look redundant, but if you move them
-:: outside of the IF clauses, they do not run properly in the SET_SDK_64==Y
-:: case, I don't know why.
-:: @ECHO OFF
-
-SET COMMAND_TO_RUN=%*
-SET WIN_SDK_ROOT=C:\Program Files\Microsoft SDKs\Windows
-SET WIN_WDK=c:\Program Files (x86)\Windows Kits\10\Include\wdf
-
-:: Extract the major and minor versions, and allow for the minor version to be
-:: more than 9.  This requires the version number to have two dots in it.
-SET MAJOR_PYTHON_VERSION=%PYTHON_VERSION:~0,1%
-IF "%PYTHON_VERSION:~3,1%" == "." (
-    SET MINOR_PYTHON_VERSION=%PYTHON_VERSION:~2,1%
-) ELSE (
-    SET MINOR_PYTHON_VERSION=%PYTHON_VERSION:~2,2%
-)
-
-:: Based on the Python version, determine what SDK version to use, and whether
-:: to set the SDK for 64-bit.
-IF %MAJOR_PYTHON_VERSION% == 2 (
-    SET WINDOWS_SDK_VERSION="v7.1"
-    SET SET_SDK_64=Y
-) ELSE (
-    IF %MAJOR_PYTHON_VERSION% == 3 (
-        SET WINDOWS_SDK_VERSION="v7.1"
-        IF %MINOR_PYTHON_VERSION% LEQ 4 (
-            SET SET_SDK_64=Y
-        ) ELSE (
-            SET SET_SDK_64=N
-            IF EXIST "%WIN_WDK%" (
-                :: See: https://connect.microsoft.com/VisualStudio/feedback/details/1610302/
-                REN "%WIN_WDK%" 0wdf
-            )
-        )
-    ) ELSE (
-        ECHO Unsupported Python version: "%MAJOR_PYTHON_VERSION%"
-        EXIT 1
-    )
-)
-
-IF %PYTHON_ARCH% == 64 (
-    call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" amd64
-    SET DISTUTILS_USE_SDK=1
-    SET MSSdk=1
-    IF %SET_SDK_64% == Y (
-::        ECHO Configuring Windows SDK %WINDOWS_SDK_VERSION% for Python %MAJOR_PYTHON_VERSION% on a 64 bit architecture
-::        "%WIN_SDK_ROOT%\%WINDOWS_SDK_VERSION%\Setup\WindowsSdkVer.exe" -q -version:%WINDOWS_SDK_VERSION%
-::        "%WIN_SDK_ROOT%\%WINDOWS_SDK_VERSION%\Bin\SetEnv.cmd" /x64 /release
-        ECHO Executing: %COMMAND_TO_RUN%
-        call %COMMAND_TO_RUN% || EXIT 1
-    ) ELSE (
-        ECHO Using default MSVC build environment for 64 bit architecture
-        ECHO Executing: %COMMAND_TO_RUN%
-        call %COMMAND_TO_RUN% || EXIT 1
-    )
-) ELSE (
-    call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86
-    SET DISTUTILS_USE_SDK=1
-    SET MSSdk=1
-    ECHO Using MSVC 14 build environment for 32 bit architecture
-    ECHO Executing: %COMMAND_TO_RUN%
-    call %COMMAND_TO_RUN% || EXIT 1
-)