diff --git a/HISTORY.rst b/HISTORY.rst
index c63cd919..51a05c9c 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -19,6 +19,7 @@ PlatformIO 4.0
   - Added support for Unix shell-style wildcards for `monitor_port <http://docs.platformio.org/page/projectconf/section_env_monitor.html#monitor-port>`__ option (`issue #2541 <https://github.com/platformio/platformio-core/issues/2541>`_)
   - Added new `monitor_flags <http://docs.platformio.org/page/projectconf/section_env_monitor.html#monitor-flags>`__ option which allows passing extra flags and options to `platformio device monitor <http://docs.platformio.org/page/userguide/cmd_device.html#cmd-device-monitor>`__ command (`issue #2165 <https://github.com/platformio/platformio-core/issues/2165>`_)
   - Override default development platform upload command with a custom `upload_command <http://docs.platformio.org/page/projectconf/section_env_upload.html#upload-command>`__ (`issue #2599 <https://github.com/platformio/platformio-core/issues/2599>`_)
+  - Added support for `PLATFORMIO_DEFAULT_ENVS <http://docs.platformio.org/page/envvars.html#envvar-PLATFORMIO_DEFAULT_ENVS>`__ system environment variable (`issue #1967 <https://github.com/platformio/platformio-core/issues/1967>`_)
   - Fixed an issue when ``-U`` in ``build_flags`` does not remove macro previously defined via ``-D`` flag (`issue #2508 <https://github.com/platformio/platformio-core/issues/2508>`_)
 
 * **Library Management**
diff --git a/docs b/docs
index c030b967..84973be5 160000
--- a/docs
+++ b/docs
@@ -1 +1 @@
-Subproject commit c030b967a5fa6d2e234f536d99ae2fe0b4d1a88d
+Subproject commit 84973be53b7465e37ab4b20ce245ffa12a294098
diff --git a/examples b/examples
index 89963fed..b5ae9ea1 160000
--- a/examples
+++ b/examples
@@ -1 +1 @@
-Subproject commit 89963fed9ebd0e7123d58dad5f7fc5020769ca63
+Subproject commit b5ae9ea1bb754d9e06b195d65f24853ef58f376d
diff --git a/platformio/project/config.py b/platformio/project/config.py
index a7001cf3..ee7e71d1 100644
--- a/platformio/project/config.py
+++ b/platformio/project/config.py
@@ -284,7 +284,7 @@ class ProjectConfig(object):
         return [s[4:] for s in self._parser.sections() if s.startswith("env:")]
 
     def default_envs(self):
-        return self.get("platformio", "env_default", [])
+        return self.get("platformio", "default_envs", [])
 
     def validate(self, envs=None, silent=False):
         if not isfile(self.path):
diff --git a/platformio/project/options.py b/platformio/project/options.py
index 1c5ff5e9..66fb13fc 100644
--- a/platformio/project/options.py
+++ b/platformio/project/options.py
@@ -48,9 +48,10 @@ ProjectOptions = OrderedDict([
         # [platformio]
         #
         ConfigPlatformioOption(name="description"),
-        ConfigPlatformioOption(name="env_default",
+        ConfigPlatformioOption(name="default_envs",
+                               oldnames=["env_default"],
                                multiple=True,
-                               sysenvvar="PLATFORMIO_ENV_DEFAULT"),
+                               sysenvvar="PLATFORMIO_DEFAULT_ENVS"),
         ConfigPlatformioOption(name="extra_configs", multiple=True),
 
         # Dirs
diff --git a/tests/test_projectconf.py b/tests/test_projectconf.py
index 1448cdb2..38725f8a 100644
--- a/tests/test_projectconf.py
+++ b/tests/test_projectconf.py
@@ -74,8 +74,8 @@ def test_real_config(tmpdir):
     with tmpdir.as_cwd():
         config = ProjectConfig(tmpdir.join("platformio.ini").strpath)
     assert config
-    assert len(config.warnings) == 1
-    assert "lib_install" in config.warnings[0]
+    assert len(config.warnings) == 2
+    assert "lib_install" in config.warnings[1]
 
     config.validate(["extra_2", "base"], silent=True)
     with pytest.raises(UnknownEnvNames):