Drop Visual Studio 2015 support

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## [1.8.0] - Unreleased
 
+- Removed: [#5760](https://github.com/ethereum/aleth/pull/5760) Official support for Visual Studio 2015 has been dropped. Compilation with this compiler is expected to stop working after migration to C++14. 
+
 ## [1.7.0] - Unreleased
 
 - Added: [#5537](https://github.com/ethereum/aleth/pull/5537) Creating Ethereum Node Record (ENR) at program start.

README.md

@@ -89,9 +89,8 @@ cmake ..               # Configure the project.
 cmake --build .        # Build all default targets.
 ```
 
-On **Windows** we support Visual Studio 2015, 2017, and 2019. You should generate a Visual Studio solution file (`.sln`) for the 64-bit architecture via the following command:
+On **Windows** we support Visual Studio 2017, and 2019. You should generate a Visual Studio solution file (`.sln`) for the 64-bit architecture via the following command:
 
-* **Visual Studio 2015**: `cmake .. -G "Visual Studio 14 2015 Win64"`
 * **Visual Studio 2017**: `cmake .. -G "Visual Studio 15 2017 Win64"`
 * **Visual Studio 2019**: `cmake .. -G "Visual Studio 16 2019" -A x64`
 

appveyor.yml

@@ -10,26 +10,27 @@ branches:
     - /release\/.+/
     - appveyor
     - hunter
-os: Visual Studio 2015
+os: Visual Studio 2017
 configuration:
   - RelWithDebInfo
 environment:
   TESTS: On
   GITHUB_USER_PASSWORD:
     secure: 7TuNppxpvI3M/IF1PfvzZ8LluCeCQAsdFoJY+KhNv/pe/rAw5HEsTjqdbyM1mEtd
-cache:
-  - build/deps -> cmake/ProjectLibFF.cmake
+# Cache disabled for Visual Studio 2017 migration
+#cache:
+#  - build/deps -> cmake/ProjectLibFF.cmake
 install:
   - git submodule update --init --recursive
 
   # Python 3
-  - set PATH=C:\Python36-x64;C:\Python36-x64\Scripts;%PATH%
+  - set PATH=C:\Python37-x64;C:\Python37-x64\Scripts;%PATH%
   - pip install requests gitpython
 
 before_build: |
   if not exist build mkdir build
   cd build
-  cmake -G "Visual Studio 14 2015 Win64" ..
+  cmake -G "Visual Studio 15 2017 Win64" ..
 build_script: |
   cmake --build . --config %CONFIGURATION% --target package
 test_script:

cmake/ProjectLibFF.cmake

@@ -1,3 +1,6 @@
+# Aleth: Ethereum C++ client, tools and libraries.
+# Copyright 2017-2019 Aleth Authors.
+# Licensed under the GNU General Public License, Version 3.
 include(ProjectMPIR)
 
 set(prefix "${CMAKE_BINARY_DIR}/deps")