diff --git a/INSTALL.md b/INSTALL.md
index 0d1b0301..a911284e 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -3,16 +3,16 @@ This guide will help you setup a development environment to launch and contribut
 
 ## Requirements
 ### AliceVision
-Meshroom relies on the [AliceVision](https://github.com/alicevision/AliceVision) framework. AliceVision's binaries must 
-be in the path while running Meshroom. 
+Meshroom relies on the [AliceVision](https://github.com/alicevision/AliceVision) framework. AliceVision's binaries must
+be in the path while running Meshroom.
 To build AliceVision, follow this [guide](https://github.com/alicevision/AliceVision/blob/develop/INSTALL.md).
 
 Meshroom also relies on specific files provided with AliceVision.
-* sensor database: a text database of sensor width per camera model. 
+* sensor database: a text database of sensor width per camera model.
 Provided in AliceVision source tree: {ALICEVISION_ROOT}/src/aliceVision/sensorDB/sensor_width_camera_database.txt
 * voctree (optional): for larger datasets (>200 images), greatly improves image matching performances.
 It can be downloaded [here](https://gitlab.com/alicevision/trainedVocabularyTreeData/raw/master/vlfeat_K80L3.SIFT.tree).
- 
+
 Environment variables must be set for Meshroom to find those files:
 ```
 ALICEVISION_SENSOR_DB=/path/to/database
@@ -20,13 +20,21 @@ ALICEVISION_VOCTREE=/path/to/voctree
 ```
 
 ### Python Environment
-* Python 2 (>= 2.7) or Python 3 (>=3.5)
+* Windows: Python 3 (>=3.5)
+* Linux: Python 3 (>=3.5) or Python 2 (>= 2.7)
+
+> No Python 2.7 support on Windows ?
+>
+> Official Python 2.7 binary package is built with Visual Studio 2008, while PySide2/Qt is built using Visual Studio 2015/2017.
+>Therefore, in order to avoid mixing MSVC runtime libraries, Qt does not ship PySide2 wheels for Python 2.7 on Windows (as explained [here](https://wiki.qt.io/Qt_for_Python/Considerations#Missing_Windows_.2F_Python_2.7_release)).
+>Note that for using Meshroom in command line mode only (no UI), PySide2 is not required and Python 2.7 would be fine.
+
 
 To install all the requirements for runtime, development and packaging, simply run:
 ```bash
 pip install -r requirements.txt -r dev_requirements.txt
 ```
-> Node: `dev_requirements` is only related to testing and packaging. It is not mandatory to run Meshroom.
+> Note: `dev_requirements` is only related to testing and packaging. It is not mandatory to run Meshroom.
 
 ### Qt Plugins
 Additional Qt plugins can be built to extend Meshroom UI features. They can be found on separate repositories,
@@ -34,7 +42,7 @@ though they might get better integration in the future.
 Note that they are optional but highly recommended.
 
 #### [QmlAlembic](https://github.com/alicevision/qmlAlembic)
-Adds support for Alembic file loading in Meshroom's 3D viewport. Allows to visualize sparse reconstruction results 
+Adds support for Alembic file loading in Meshroom's 3D viewport. Allows to visualize sparse reconstruction results
 (point cloud and cameras).
 ```
 QML2_IMPORT_PATH=/path/to/qmlAlembic/install/qml
diff --git a/requirements.txt b/requirements.txt
index f5087aa2..3c3a18a2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,4 @@
 # runtime
 psutil
 enum34;python_version<"3.4"
-
---extra-index-url https://download.qt.io/snapshots/ci/pyside/5.11/latest/
-pyside2
+PySide2==5.11.0