diff --git a/requirements.txt b/requirements.txt
index 76e9c6b549..9a0b2d2933 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,11 +11,13 @@ future>=0.15.2
 cryptography>=2.1.4
 pyparsing>=2.0.3,<2.4.0
 pyelftools>=0.22
+
 gdbgui==0.13.2.0
 # 0.13.2.1 supports Python 3.6+ only
 # Windows is not supported since 0.14.0.0. See https://github.com/cs01/gdbgui/issues/348
 pygdbmi<=0.9.0.2
 # The pygdbmi required max version 0.9.0.2 since 0.9.0.3 is not copatible with latest gdbgui (>=0.13.2.0)
+python-socketio<5; python_version<="2.7"
 
 # esptool requirements (see components/esptool_py/esptool/setup.py)
 reedsolo>=1.5.3,<=1.5.4