diff --git a/windows/client-management/mdm/TOC.md b/windows/client-management/mdm/TOC.md
index 1ac5a9f388..ca5fd03714 100644
--- a/windows/client-management/mdm/TOC.md
+++ b/windows/client-management/mdm/TOC.md
@@ -155,6 +155,8 @@
#### [Maps DDF](maps-ddf-file.md)
### [Messaging CSP](messaging-csp.md)
#### [Messaging DDF file](messaging-ddf.md)
+### [MultiSIM CSP](multisim-csp.md)
+#### [MultiSIM DDF file](multisim-ddf.md)
### [NAP CSP](nap-csp.md)
### [NAPDEF CSP](napdef-csp.md)
### [NetworkProxy CSP](networkproxy-csp.md)
diff --git a/windows/client-management/mdm/configuration-service-provider-reference.md b/windows/client-management/mdm/configuration-service-provider-reference.md
index 16f80bc1f1..e7ed3131c8 100644
--- a/windows/client-management/mdm/configuration-service-provider-reference.md
+++ b/windows/client-management/mdm/configuration-service-provider-reference.md
@@ -1295,6 +1295,34 @@ Footnotes:
+
+[MultiSIM CSP](multisim-csp.md)
+
+
+
+
+ Home |
+ Pro |
+ Business |
+ Enterprise |
+ Education |
+ Mobile |
+ Mobile Enterprise |
+
+
+ 4 |
+ 4 |
+ 4 |
+ 4 |
+ 4 |
+ 4 |
+ 4 |
+
+
+
+
+
+
[NAP CSP](nap-csp.md)
diff --git a/windows/client-management/mdm/images/provisioning-csp-multisim.png b/windows/client-management/mdm/images/provisioning-csp-multisim.png
new file mode 100644
index 0000000000..86473079f4
Binary files /dev/null and b/windows/client-management/mdm/images/provisioning-csp-multisim.png differ
diff --git a/windows/client-management/mdm/multisim-csp.md b/windows/client-management/mdm/multisim-csp.md
new file mode 100644
index 0000000000..9467b896ff
--- /dev/null
+++ b/windows/client-management/mdm/multisim-csp.md
@@ -0,0 +1,58 @@
+---
+title: MultiSIM CSP
+description: MultiSIM CSP allows the enterprise to manage devices with dual SIM single active configuration.
+ms.author: maricia
+ms.topic: article
+ms.prod: w10
+ms.technology: windows
+author: nickbrower
+ms.date: 02/27/2018
+---
+
+# MultiSIM CSP
+
+> [!WARNING]
+> Some information relates to prereleased product which may be substantially modified before it's commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
+
+The MultiSIM configuration service provider (CSP) is used by the enterprise to manage devices with dual SIM single active configuration. An enterprise can set policies on whether that user can switch between SIM slots, specify which slot is the default, and whether the slot is embedded. This CSP was added in Windows 10, version 1803.
+
+
+The following diagram shows the MultiSIM configuration service provider in tree format.
+
+
+
+**./Device/Vendor/MSFT/MultiSIM**
+Root node.
+
+**_ModemID_**
+Node representing a Mobile Broadband Modem. The node name is the modem ID. Modem ID is a GUID without curly braces, with exception of "Embedded" which represents the embedded modem.
+
+**_ModemID_/Identifier**
+Modem ID.
+
+**_ModemID_/IsEmbedded**
+Indicates whether this modem is embedded or external.
+
+**_ModemID_/Slots**
+Represents all SIM slots in the Modem.
+
+**_ModemID_/Slots/_SlotID_**
+Node representing a SIM Slot. The node name is the Slot ID. SIM Slot ID format is "0", "1", etc., with exception of "Embedded" which represents the embedded Slot.
+
+**_ModemID_/Slots/_SlotID_/Identifier**
+Slot ID.
+
+**_ModemID_/Slots/_SlotID_/IsEmbedded**
+Indicates whether this Slot is embedded or a physical SIM slot.
+
+**_ModemID_/Slots/_SlotID_/IsSelected**
+Indicates whether this Slot is selected or not.
+
+**_ModemID_/Slots/_SlotID_/State**
+Slot state (Unknown = 0, OffEmpty = 1, Off = 2, Empty = 3, NotReady = 4, Active = 5, Error = 6, ActiveEsim = 7, ActiveEsimNoProfile = 8)
+
+**_ModemID_/Policies**
+Policies associated with the Modem.
+
+**_ModemID_/Policies/SlotSelectionEnabled**
+Determines whether the user is allowed to change slots in the Cellular settings UI. Default is true.
\ No newline at end of file
diff --git a/windows/client-management/mdm/multisim-ddf.md b/windows/client-management/mdm/multisim-ddf.md
new file mode 100644
index 0000000000..ccdbecbaee
--- /dev/null
+++ b/windows/client-management/mdm/multisim-ddf.md
@@ -0,0 +1,291 @@
+---
+title: MultiSIM DDF file
+description: XML file containing the device description framework
+ms.author: maricia
+ms.topic: article
+ms.prod: w10
+ms.technology: windows
+author: nickbrower
+ms.date: 02/27/2018
+---
+
+# MultiSIM CSP
+
+> [!WARNING]
+> Some information relates to prereleased product which may be substantially modified before it's commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
+
+This topic shows the OMA DM device description framework (DDF) for the **MultiSIM** configuration service provider.
+
+The XML below is for Windows 10, version 1803.
+
+``` syntax
+
+]>
+
+ 1.2
+
+ MultiSIM
+ ./Device/Vendor/MSFT
+
+
+
+
+ Subtree for multi-SIM management.
+
+
+
+
+
+
+
+
+
+
+ com.microsoft/1.0/MDM/MultiSIM
+
+
+
+
+
+
+
+
+
+ Node representing a Mobile Broadband Modem. The node name is the Modem ID. Modem ID is a GUID without curly braces, with exception of "Embedded" which represents the embedded Modem.
+
+
+
+
+
+
+
+
+
+ ModemID
+
+
+
+
+
+ Identifier
+
+
+
+
+ Modem ID.
+
+
+
+
+
+
+
+
+
+
+
+
+
+ text/plain
+
+
+
+
+ IsEmbedded
+
+
+
+
+ Indicates whether this Modem is embedded or external.
+
+
+
+
+
+
+
+
+
+
+ text/plain
+
+
+
+
+ Slots
+
+
+
+
+ Represents all SIM slots in the Modem.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ Node representing a SIM Slot. The node name is the Slot ID. SIM Slot ID format is "0", "1", etc., with exception of "Embedded" which represents the embedded Slot.
+
+
+
+
+
+
+
+
+
+ SlotID
+
+
+
+
+
+ Identifier
+
+
+
+
+ Slot ID.
+
+
+
+
+
+
+
+
+
+
+ text/plain
+
+
+
+
+ IsEmbedded
+
+
+
+
+ Indicates whether this Slot is embedded or a physical SIM slot.
+
+
+
+
+
+
+
+
+
+
+ text/plain
+
+
+
+
+ IsSelected
+
+
+
+
+
+ Indicates whether this Slot is selected or not.
+
+
+
+
+
+
+
+
+
+
+ text/plain
+
+
+
+
+ State
+
+
+
+
+ Slot state (Unknown = 0, OffEmpty = 1, Off = 2, Empty = 3, NotReady = 4, Active = 5, Error = 6, ActiveEsim = 7, ActiveEsimNoProfile = 8)
+
+
+
+
+
+
+
+
+
+
+ text/plain
+
+
+
+
+
+
+ Policies
+
+
+
+
+ Policies associated with the Modem.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ SlotSelectionEnabled
+
+
+
+
+
+ true
+ Determines whether the user is allowed to change slots in the Cellular settings UI. Default is true.
+
+
+
+
+
+
+
+
+
+
+ text/plain
+
+
+
+
+
+
+
+```
\ No newline at end of file
diff --git a/windows/client-management/mdm/new-in-windows-mdm-enrollment-management.md b/windows/client-management/mdm/new-in-windows-mdm-enrollment-management.md
index 4ff04b5dba..46bd55a93f 100644
--- a/windows/client-management/mdm/new-in-windows-mdm-enrollment-management.md
+++ b/windows/client-management/mdm/new-in-windows-mdm-enrollment-management.md
@@ -1436,6 +1436,10 @@ The DM agent for [push-button reset](https://msdn.microsoft.com/windows/hardware
Updated the AssigneAccessConfiguration schema.
+
+[MultiSIM CSP](multisim-csp.md) |
+Added a new CSP in Windows 10, version 1803.
+ |