diff --git a/.github/workflows/build-cache-deps.yml b/.github/workflows/build-cache-deps.yml
index ea6ece07..06f9387c 100644
--- a/.github/workflows/build-cache-deps.yml
+++ b/.github/workflows/build-cache-deps.yml
@@ -39,17 +39,11 @@ jobs:
       - name: Install cibuildwheel & twine
         run: python3 -m pip install cibuildwheel twine
 
-      - name: manylinux preparations
-        if: matrix.cibw_buildlinux == 'manylinux'
-        run: echo INSTALL_OS_PACKAGES="yum makecache && yum install -y $OS_PACKAGES" >> $GITHUB_ENV
-        env:
-          OS_PACKAGES: "git-all"
-
-      - name: musllinux preparations
-        if: matrix.cibw_buildlinux == 'musllinux'
+      - name: 32-bit musllinux preparations
+        if: matrix.cibw_buildlinux == 'musllinux' && matrix.cibw_arch == 'i686'
         run: echo INSTALL_OS_PACKAGES="apk update && apk --no-cache add $OS_PACKAGES" >> $GITHUB_ENV
         env:
-          OS_PACKAGES: "sudo py3-pip python3-dev fribidi-dev harfbuzz-dev jpeg-dev lcms2-dev openjpeg-dev"
+          OS_PACKAGES: "fribidi-dev harfbuzz-dev jpeg-dev lcms2-dev openjpeg-dev"
 
       - uses: actions/cache@v3
         with:
diff --git a/.github/workflows/publish-pypi-pi_heif.yml b/.github/workflows/publish-pypi-pi_heif.yml
index 2c85a82e..5a748665 100644
--- a/.github/workflows/publish-pypi-pi_heif.yml
+++ b/.github/workflows/publish-pypi-pi_heif.yml
@@ -14,7 +14,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-
       - name: Transform to Pi-Heif
         run: |
           cp -r -v -force ./pi-heif/* .
@@ -66,7 +65,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-
       - name: Transform to Pi-Heif
         run: |
           cp -r -v ./pi-heif/* .
@@ -106,7 +104,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-
       - name: Transform to Pi-Heif
         run: |
           cp -r -v ./pi-heif/* .
@@ -118,17 +115,11 @@ jobs:
         with:
           platforms: arm64
 
-      - name: manylinux preparations
-        if: matrix.cibw_buildlinux == 'manylinux'
-        run: echo INSTALL_OS_PACKAGES="yum makecache && yum install -y $OS_PACKAGES" >> $GITHUB_ENV
-        env:
-          OS_PACKAGES: "git-all libjpeg-turbo-devel lcms2-devel libffi-devel"
-
       - name: musllinux preparations
         if: matrix.cibw_buildlinux == 'musllinux'
         run: echo INSTALL_OS_PACKAGES="apk update && apk --no-cache add $OS_PACKAGES" >> $GITHUB_ENV
         env:
-          OS_PACKAGES: "sudo py3-pip python3-dev fribidi-dev harfbuzz-dev jpeg-dev lcms2-dev openjpeg-dev"
+          OS_PACKAGES: "fribidi-dev harfbuzz-dev jpeg-dev lcms2-dev openjpeg-dev"
 
       - name: Run cibuildwheel
         run: |
@@ -158,7 +149,7 @@ jobs:
       matrix:
         cibw_buildlinux: [ manylinux ]
         cibw_arch: [ "aarch64", "i686", "x86_64" ]
-        cibw_build: [ "pp37", "pp38" ]
+        cibw_build: [ "pp38", "pp39" ]
     name: ${{ matrix.cibw_buildlinux }} • ${{ matrix.cibw_arch }} • ${{ matrix.cibw_build }}
     runs-on: ubuntu-20.04
     env:
@@ -167,7 +158,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-
       - name: Transform to Pi-Heif
         run: |
           cp -r -v ./pi-heif/* .
@@ -186,7 +176,7 @@ jobs:
         env:
           CIBW_BUILD: ${{ format('{0}-{1}_{2}', matrix.cibw_build , matrix.cibw_buildlinux, matrix.cibw_arch) }}
           CIBW_ARCHS: ${{ matrix.cibw_arch }}
-          CIBW_BEFORE_ALL_LINUX: "yum makecache && yum install -y git-all libjpeg-turbo-devel lcms2-devel libffi-devel"
+          CIBW_BEFORE_ALL_LINUX: "yum makecache && yum install -y libjpeg-turbo-devel lcms2-devel"
           CIBW_ENVIRONMENT_LINUX: BUILD_DIR_PREFIX=/host${{ env.BUILD_DIR_PREFIX }} PH_LIGHT_ACTION=1
 
       - name: Checking built wheels
@@ -213,7 +203,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-
       - name: Transform to Pi-Heif
         run: |
           cp -r -v ./pi-heif/* .
@@ -250,7 +239,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-
       - name: Transform to Pi-Heif
         run: |
           cp -r -v ./pi-heif/* .
@@ -285,7 +273,7 @@ jobs:
 
       - name: Test sdist
         run: |
-          export PH_LIGHT_ACTION=1
+          export PH_LIGHT_ACTION=1 TEST_DECODE_THREADS=0
           python3 -m pytest -rs
 
       - name: Upload sdist
diff --git a/.github/workflows/publish-pypi.yml b/.github/workflows/publish-pypi.yml
index bbf803c2..0b31dead 100644
--- a/.github/workflows/publish-pypi.yml
+++ b/.github/workflows/publish-pypi.yml
@@ -17,7 +17,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v2
 
@@ -51,7 +50,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-
       - uses: msys2/setup-msys2@v2
         with:
           location: C:/temp
@@ -138,17 +136,11 @@ jobs:
         with:
           platforms: arm64
 
-      - name: manylinux preparations
-        if: matrix.cibw_buildlinux == 'manylinux'
-        run: echo INSTALL_OS_PACKAGES="yum makecache && yum install -y $OS_PACKAGES" >> $GITHUB_ENV
-        env:
-          OS_PACKAGES: "git-all libjpeg-turbo-devel lcms2-devel libffi-devel"
-
       - name: musllinux preparations
         if: matrix.cibw_buildlinux == 'musllinux'
         run: echo INSTALL_OS_PACKAGES="apk update && apk --no-cache add $OS_PACKAGES" >> $GITHUB_ENV
         env:
-          OS_PACKAGES: "sudo py3-pip python3-dev fribidi-dev harfbuzz-dev jpeg-dev lcms2-dev openjpeg-dev"
+          OS_PACKAGES: "fribidi-dev harfbuzz-dev jpeg-dev lcms2-dev openjpeg-dev"
 
       - name: Only minimal testing on aarch64
         if: matrix.cibw_arch == 'aarch64'
@@ -207,17 +199,11 @@ jobs:
         with:
           platforms: arm64
 
-      - name: manylinux preparations
-        if: matrix.cibw_buildlinux == 'manylinux'
-        run: echo INSTALL_OS_PACKAGES="yum makecache && yum install -y $OS_PACKAGES" >> $GITHUB_ENV
-        env:
-          OS_PACKAGES: "git-all libjpeg-turbo-devel lcms2-devel libffi-devel"
-
       - name: musllinux preparations
         if: matrix.cibw_buildlinux == 'musllinux'
         run: echo INSTALL_OS_PACKAGES="apk update && apk --no-cache add $OS_PACKAGES" >> $GITHUB_ENV
         env:
-          OS_PACKAGES: "sudo py3-pip python3-dev fribidi-dev harfbuzz-dev jpeg-dev lcms2-dev openjpeg-dev"
+          OS_PACKAGES: "fribidi-dev harfbuzz-dev jpeg-dev lcms2-dev openjpeg-dev"
 
       - name: Only minimal testing on aarch64
         if: matrix.cibw_arch == 'aarch64'
@@ -262,7 +248,7 @@ jobs:
       matrix:
         cibw_buildlinux: [ manylinux ]
         cibw_arch: [ "aarch64", "x86_64" ]
-        cibw_build: [ "pp37", "pp38" ]
+        cibw_build: [ "pp38", "pp39" ]
     name: ${{ matrix.cibw_buildlinux }} • ${{ matrix.cibw_arch }} • ${{ matrix.cibw_build }}
     runs-on: ubuntu-20.04
     env:
@@ -296,7 +282,7 @@ jobs:
         env:
           CIBW_BUILD: ${{ format('{0}-{1}_{2}', matrix.cibw_build , matrix.cibw_buildlinux, matrix.cibw_arch) }}
           CIBW_ARCHS: ${{ matrix.cibw_arch }}
-          CIBW_BEFORE_ALL_LINUX: "yum makecache && yum install -y git-all libjpeg-turbo-devel lcms2-devel libffi-devel"
+          CIBW_BEFORE_ALL_LINUX: "yum makecache && yum install -y libjpeg-turbo-devel lcms2-devel"
           CIBW_ENVIRONMENT_LINUX: BUILD_DIR_PREFIX=/host${{ env.BUILD_DIR_PREFIX }} PH_FULL_ACTION=1
 
       - name: Checking built wheels
@@ -320,7 +306,7 @@ jobs:
       matrix:
         cibw_buildlinux: [ manylinux ]
         cibw_arch: [ "i686" ]
-        cibw_build: [ "pp37", "pp38" ]
+        cibw_build: [ "pp38", "pp39" ]
     name: ${{ matrix.cibw_buildlinux }} • ${{ matrix.cibw_arch }} • ${{ matrix.cibw_build }}
     runs-on: ubuntu-20.04
     env:
@@ -354,7 +340,6 @@ jobs:
         env:
           CIBW_BUILD: ${{ format('{0}-{1}_{2}', matrix.cibw_build , matrix.cibw_buildlinux, matrix.cibw_arch) }}
           CIBW_ARCHS: ${{ matrix.cibw_arch }}
-          CIBW_BEFORE_ALL_LINUX: "yum makecache && yum install -y git-all libjpeg-turbo-devel lcms2-devel libffi-devel"
           CIBW_ENVIRONMENT_LINUX: BUILD_DIR_PREFIX=/host${{ env.BUILD_DIR_PREFIX }} PH_LIGHT_ACTION=1
 
       - name: Checking built wheels
@@ -378,7 +363,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-
       - uses: actions/setup-python@v4
         with:
           python-version: '3.10'
@@ -409,7 +393,7 @@ jobs:
 
       - name: Test sdist
         run: |
-          export PH_FULL_ACTION=1
+          export PH_FULL_ACTION=1 TEST_DECODE_THREADS=0
           python3 -m pytest -rs
 
       - name: Upload sdist
diff --git a/.github/workflows/test-wheels-pi_heif.yml b/.github/workflows/test-wheels-pi_heif.yml
index 44878c39..d36674f2 100644
--- a/.github/workflows/test-wheels-pi_heif.yml
+++ b/.github/workflows/test-wheels-pi_heif.yml
@@ -110,7 +110,7 @@ jobs:
     runs-on: macos-11
     strategy:
       matrix:
-        python-version: ["pypy-3.7", "pypy-3.8", "3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["pypy-3.8", "pypy-3.9", "3.7", "3.8", "3.9", "3.10", "3.11"]
 
     steps:
       - name: Delay, waiting Pypi to update.
@@ -146,7 +146,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: ["pypy-3.7", "pypy-3.8", "3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["pypy-3.8", "pypy-3.9", "3.7", "3.8", "3.9", "3.10", "3.11"]
 
     steps:
       - name: Delay, waiting Pypi to update.
diff --git a/.github/workflows/test-wheels.yml b/.github/workflows/test-wheels.yml
index 6dde6485..259c1485 100644
--- a/.github/workflows/test-wheels.yml
+++ b/.github/workflows/test-wheels.yml
@@ -115,7 +115,7 @@ jobs:
     runs-on: macos-11
     strategy:
       matrix:
-        python-version: ["pypy-3.7", "pypy-3.8", "3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["pypy-3.8", "pypy-3.9", "3.7", "3.8", "3.9", "3.10", "3.11"]
 
     steps:
       - name: Delay, waiting Pypi to update.
@@ -150,7 +150,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: ["pypy-3.7", "pypy-3.8", "3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["pypy-3.8", "pypy-3.9", "3.7", "3.8", "3.9", "3.10", "3.11"]
 
     steps:
       - name: Delay, waiting Pypi to update.