diff --git a/HISTORY.rst b/HISTORY.rst
index 4555f655..83d20732 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -7,6 +7,9 @@ PlatformIO 3.0
 3.5.2 (2018-??-??)
 ~~~~~~~~~~~~~~~~~~
 
+* Control `PIO Unified Debugger <http://docs.platformio.org/en/latest/plus/debugging.html>`__
+  and its firmware loading mode using
+  `debug_load_mode <http://docs.platformio.org/en/latest/projectconf/section_env_debug.html#debug-load-mode>`__ option
 * Added aliases (off, light, strict) for
   `LDF Compatibility Mode <http://docs.platformio.org/page/librarymanager/ldf.html>`__
 * Search for a library using PIO Library Registry ID ``id:X`` (e.g. ``pio lib search id:13``)
diff --git a/docs b/docs
index e050d472..a77f8fc8 160000
--- a/docs
+++ b/docs
@@ -1 +1 @@
-Subproject commit e050d472ea75ae8cd088da1d4b3fc37cd8e2b245
+Subproject commit a77f8fc882916e68c12dcc275cdc8145f26b5888
diff --git a/platformio/commands/run.py b/platformio/commands/run.py
index 14db42a7..50ff22b0 100644
--- a/platformio/commands/run.py
+++ b/platformio/commands/run.py
@@ -137,15 +137,16 @@ class EnvironmentProcessor(object):
                      "test_ignore", "test_port", "test_speed", "debug_tool",
                      "debug_port", "debug_init_cmds", "debug_extra_cmds",
                      "debug_server", "debug_init_break", "debug_load_cmd",
-                     "monitor_port", "monitor_baud", "monitor_rts",
-                     "monitor_dtr")
+                     "debug_load_mode", "monitor_port", "monitor_baud",
+                     "monitor_rts", "monitor_dtr")
 
     IGNORE_BUILD_OPTIONS = ("test_transport", "test_filter", "test_ignore",
                             "test_port", "test_speed", "debug_port",
                             "debug_init_cmds", "debug_extra_cmds",
                             "debug_server", "debug_init_break",
-                            "debug_load_cmd", "monitor_port", "monitor_baud",
-                            "monitor_rts", "monitor_dtr")
+                            "debug_load_cmd", "debug_load_mode",
+                            "monitor_port", "monitor_baud", "monitor_rts",
+                            "monitor_dtr")
 
     REMAPED_OPTIONS = {"framework": "pioframework", "platform": "pioplatform"}
 
diff --git a/platformio/managers/core.py b/platformio/managers/core.py
index 9789b763..024bf8a1 100644
--- a/platformio/managers/core.py
+++ b/platformio/managers/core.py
@@ -23,7 +23,7 @@ from platformio.managers.package import PackageManager
 CORE_PACKAGES = {
     "contrib-piohome": ">=0.6.1,<2",
     "contrib-pysite": ">=0.1.2,<2",
-    "tool-pioplus": ">=0.13.5,<2",
+    "tool-pioplus": ">=0.14.0,<2",
     "tool-unity": "~1.20302.1",
     "tool-scons": "~2.20501.3"
 }