diff --git a/.travis.yml b/.travis.yml
index b01e6d36..b34ca94b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -424,6 +424,210 @@ matrix:
         - additional_defines=""
         - MATRIX_EVAL="CC=gcc-8 && CXX=g++-8"
 
+    - os: linux
+      compiler: clang
+      name: ubuntu 14.04 - native clang - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL=""
+
+    - os: linux
+      compiler: clang
+      name: ubuntu 14.04 - clang@3.6 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+            - clang-3.6
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=clang-3.6 && CXX=clang++-3.6"
+
+    - os: linux
+      compiler: clang
+      name: ubuntu 14.04 - clang@3.8 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - llvm-toolchain-precise-3.8
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+            - clang-3.8
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=clang-3.8 && CXX=clang++-3.8"
+
+    - os: linux
+      compiler: clang
+      name: ubuntu 14.04 - clang@3.9 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - llvm-toolchain-trusty-3.9
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+            - clang-3.9
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=clang-3.9 && CXX=clang++-3.9"
+
+    - os: linux
+      compiler: clang
+      name: ubuntu 14.04 - clang@4.0 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - llvm-toolchain-trusty-4.0
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+            - clang-4.0
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=clang-4.0 && CXX=clang++-4.0"
+
+    - os: linux
+      compiler: clang
+      name: ubuntu 14.04 - clang@5.0 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - llvm-toolchain-trusty-5.0
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+            - clang-5.0
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=clang-5.0 && CXX=clang++-5.0"
+
+    - os: linux
+      compiler: clang
+      name: ubuntu 14.04 - clang@6.0 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - llvm-toolchain-trusty-6.0
+            - ubuntu-toolchain-r-test
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+            - clang-6.0
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=clang-6.0 && CXX=clang++-6.0"
+
+    - os: linux
+      compiler: gcc
+      name: ubuntu 14.04 - native gcc - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL=""
+
+    - os: linux
+      compiler: gcc
+      name: ubuntu 14.04 - gcc@4.9 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - ubuntu-toolchain-r-test
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+            - g++-4.9
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=gcc-4.9 && CXX=g++-4.9"
+
+    - os: linux
+      compiler: gcc
+      name: ubuntu 14.04 - gcc@5.0 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - ubuntu-toolchain-r-test
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+            - g++-5
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=gcc-5 && CXX=g++-5"
+
+    - os: linux
+      compiler: gcc
+      name: ubuntu 14.04 - gcc@6.0 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - ubuntu-toolchain-r-test
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - g++-6
+            - libopencv-dev
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=gcc-6 && CXX=g++-6"
+
+    - os: linux
+      compiler: gcc
+      name: ubuntu 14.04 - gcc@7.0 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - ubuntu-toolchain-r-test
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+            - g++-7
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=gcc-7 && CXX=g++-7"
+
+    - os: linux
+      compiler: gcc
+      name: ubuntu 14.04 - gcc@8.0 - opencv@3
+      addons:
+        apt:
+          update: true
+          sources:
+            - ubuntu-toolchain-r-test
+            - sourceline: 'ppa:timsc/opencv-3.4'
+          packages:
+            - libopencv-dev
+            - g++-8
+      env:
+        - additional_defines=""
+        - MATRIX_EVAL="CC=gcc-8 && CXX=g++-8"
+
     - os: linux
       compiler: clang
       name: ubuntu 14.04 - native clang - CUDA 10 - opencv@2
diff --git a/appveyor.yml b/appveyor.yml
index 0860ce29..911ed3d1 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,5 +1,6 @@
 image: Visual Studio 2017
 clone_folder: c:\projects\darknet
+cache: C:\Tools\vcpkg\installed\
 
 environment:
     WORKSPACE: C:\projects
@@ -11,25 +12,25 @@ environment:
     - platform: Win64
       COMPILER: vs
       configuration: Release
-      VCPKG_ROOT: C:\projects\vcpkg
+      VCPKG_ROOT: C:\Tools\vcpkg
       VCPKG_DEFAULT_TRIPLET: x64-windows
       USE_CUDA: yes
     - platform: Win64
       COMPILER: vs
       configuration: Debug
-      VCPKG_ROOT: C:\projects\vcpkg
+      VCPKG_ROOT: C:\Tools\vcpkg
       VCPKG_DEFAULT_TRIPLET: x64-windows
       USE_CUDA: yes
     - platform: Win64
       COMPILER: vs
       configuration: Release
-      VCPKG_ROOT: C:\projects\vcpkg
+      VCPKG_ROOT: C:\Tools\vcpkg
       VCPKG_DEFAULT_TRIPLET: x64-windows
       USE_CUDA: no
     - platform: Win64
       COMPILER: vs
       configuration: Debug
-      VCPKG_ROOT: C:\projects\vcpkg
+      VCPKG_ROOT: C:\Tools\vcpkg
       VCPKG_DEFAULT_TRIPLET: x64-windows
       USE_CUDA: no
     - platform: Win64
@@ -62,10 +63,9 @@ install:
   - if [%COMPILER%]==[cygwin] %CYGSH% 'make -j8'
   - if [%COMPILER%]==[cygwin] %CYGSH% 'make install'
   - if [%COMPILER%]==[cygwin] cd %WORKSPACE%
-  - if [%COMPILER%]==[vs] if NOT [%USE_INTEGRATED_LIBS%]==[yes] git clone https://github.com/Microsoft/vcpkg
   - if [%COMPILER%]==[vs] if NOT [%USE_INTEGRATED_LIBS%]==[yes] cd %VCPKG_ROOT%
-  - if [%COMPILER%]==[vs] if NOT [%USE_INTEGRATED_LIBS%]==[yes] bootstrap-vcpkg.bat
-  - if [%COMPILER%]==[vs] if NOT [%USE_INTEGRATED_LIBS%]==[yes] vcpkg integrate install
+  - if [%COMPILER%]==[vs] if NOT [%USE_INTEGRATED_LIBS%]==[yes] git pull
+  - if [%COMPILER%]==[vs] if NOT [%USE_INTEGRATED_LIBS%]==[yes] .\bootstrap-vcpkg.bat
   - if [%COMPILER%]==[vs] if NOT [%USE_INTEGRATED_LIBS%]==[yes] if [%USE_CUDA%]==[yes] vcpkg install cuda
   - if [%COMPILER%]==[vs] if NOT [%USE_INTEGRATED_LIBS%]==[yes] vcpkg install opencv[ffmpeg] pthreads   ## opencv[ffmpeg,cuda] is too big to build, timing out (>1h). We use plain openCV also for CUDA builds (toolchain can manage this strange situation anyway)
   - cd %WORKSPACE%\darknet\