diff --git a/src/skins/vector/css/_common.scss b/src/skins/vector/css/_common.scss
index 5e0b902a..a2b7399e 100644
--- a/src/skins/vector/css/_common.scss
+++ b/src/skins/vector/css/_common.scss
@@ -83,7 +83,6 @@ textarea {
 /* applied to side-panels and messagepanel when in RoomSettings */
 .mx_fadable {
     opacity: 1;
-    -ms-transition: opacity 0.2s ease-in-out;
     -o-transition: opacity 0.2s ease-in-out;
 }
 
@@ -126,7 +125,6 @@ textarea {
     width: 100%;
     height: 100%;
 
-    display: -ms-flexbox;
     display: flex;
     align-items: center;
     justify-content: center;
diff --git a/src/skins/vector/css/matrix-react-sdk/structures/_FilePanel.scss b/src/skins/vector/css/matrix-react-sdk/structures/_FilePanel.scss
index 2fb1131d..872085b6 100644
--- a/src/skins/vector/css/matrix-react-sdk/structures/_FilePanel.scss
+++ b/src/skins/vector/css/matrix-react-sdk/structures/_FilePanel.scss
@@ -15,7 +15,6 @@ limitations under the License.
 */
 
 .mx_FilePanel {
-    -ms-flex-order: 2;
     order: 2;
 
     flex: 1 1 0;
diff --git a/src/skins/vector/css/matrix-react-sdk/structures/_MatrixChat.scss b/src/skins/vector/css/matrix-react-sdk/structures/_MatrixChat.scss
index 72f1feff..05a39ea7 100644
--- a/src/skins/vector/css/matrix-react-sdk/structures/_MatrixChat.scss
+++ b/src/skins/vector/css/matrix-react-sdk/structures/_MatrixChat.scss
@@ -27,7 +27,6 @@ limitations under the License.
 }
 
 .mx_MatrixChat_wrapper {
-    display: -ms-flexbox;
     display: flex;
 
     flex-direction: column;
@@ -37,14 +36,12 @@ limitations under the License.
 }
 
 .mx_MatrixToolbar {
-    -ms-flex-order: 1;
     order: 1;
 
     height: 40px;
 }
 
 .mx_GuestWarningBar {
-    -ms-flex-order: 1;
     order: 1;
 
     height: 40px;
@@ -58,17 +55,14 @@ limitations under the License.
     width: 100%;
     height: 100%;
 
-    display: -ms-flexbox;
     display: flex;
 
-    -ms-flex-order: 2;
     order: 2;
 
     flex: 1;
 }
 
 .mx_MatrixChat .mx_LeftPanel {
-    -ms-flex-order: 1;
     order: 1;
 
     background-color: $secondary-accent-color;
@@ -81,7 +75,6 @@ limitations under the License.
 }
 
 .mx_MatrixChat .mx_MatrixChat_middlePanel {
-    -ms-flex-order: 2;
     order: 2;
 
     padding-left: 20px;
@@ -106,12 +99,10 @@ limitations under the License.
      * point, but instead we fudge it and make the middlePanel
      * flex itself.
      */
-    display: -ms-flexbox;
     display: flex;
 }
 
 .mx_MatrixChat .mx_RightPanel {
-    -ms-flex-order: 3;
     order: 3;
 
     flex: 0 0 235px;
diff --git a/src/skins/vector/css/matrix-react-sdk/structures/_NotificationPanel.scss b/src/skins/vector/css/matrix-react-sdk/structures/_NotificationPanel.scss
index b3f724d8..ef75678d 100644
--- a/src/skins/vector/css/matrix-react-sdk/structures/_NotificationPanel.scss
+++ b/src/skins/vector/css/matrix-react-sdk/structures/_NotificationPanel.scss
@@ -15,7 +15,6 @@ limitations under the License.
 */
 
 .mx_NotificationPanel {
-    -ms-flex-order: 2;
     order: 2;
 
     flex: 1 1 0;
diff --git a/src/skins/vector/css/matrix-react-sdk/structures/_RoomView.scss b/src/skins/vector/css/matrix-react-sdk/structures/_RoomView.scss
index 6a5db95a..919b9f9b 100644
--- a/src/skins/vector/css/matrix-react-sdk/structures/_RoomView.scss
+++ b/src/skins/vector/css/matrix-react-sdk/structures/_RoomView.scss
@@ -18,7 +18,6 @@ limitations under the License.
     word-wrap: break-word;
     position: relative;
 
-    display: -ms-flexbox;
     display: flex;
     width: 100%;
 
@@ -26,7 +25,6 @@ limitations under the License.
 }
 
 .mx_RoomView .mx_RoomHeader {
-    -ms-flex-order: 1;
     order: 1;
 
     flex: 0 0 70px;
@@ -65,7 +63,6 @@ limitations under the License.
 }
 
 .mx_RoomView_auxPanel {
-    -ms-flex-order: 2;
     order: 2;
 
     min-width: 0px;
@@ -80,12 +77,10 @@ limitations under the License.
 }
 
 .mx_RoomView_topUnreadMessagesBar {
-    -ms-flex-order: 3;
     order: 3;
 }
 
 .mx_RoomView_messagePanel {
-    -ms-flex-order: 4;
     order: 4;
 
     flex: 1 1 0;
@@ -101,7 +96,6 @@ limitations under the License.
 
     min-height: 100%;
 
-    display: -ms-flexbox;
     display: flex;
 
     flex-direction: column;
@@ -133,7 +127,6 @@ limitations under the License.
 }
 
 .mx_RoomView_invitePrompt {
-    -ms-flex-order: 2;
     order: 2;
 
     min-width: 0px;
@@ -161,7 +154,6 @@ hr.mx_RoomView_myReadMarker {
 }
 
 .mx_RoomView_statusArea {
-    -ms-flex-order: 5;
     order: 5;
 
     width: 100%;
@@ -221,7 +213,6 @@ hr.mx_RoomView_myReadMarker {
 }
 
 .mx_RoomView .mx_MessageComposer {
-    -ms-flex-order: 6;
     order: 6;
 
     width: 100%;
diff --git a/src/skins/vector/css/matrix-react-sdk/structures/_UserSettings.scss b/src/skins/vector/css/matrix-react-sdk/structures/_UserSettings.scss
index d190e32c..5c1b4c5c 100644
--- a/src/skins/vector/css/matrix-react-sdk/structures/_UserSettings.scss
+++ b/src/skins/vector/css/matrix-react-sdk/structures/_UserSettings.scss
@@ -20,20 +20,17 @@ limitations under the License.
     margin-left: auto;
     margin-right: auto;
 
-    display: -ms-flexbox;
     display: flex;
     flex-direction: column;
 }
 
 .mx_UserSettings .mx_RoomHeader {
-    -ms-flex-order: 1;
     order: 1;
 
     flex: 0 0 70px;
 }
 
 .mx_UserSettings_body {
-    -ms-flex-order: 2;
     order: 2;
 
     flex: 1 1 0;
diff --git a/src/skins/vector/css/matrix-react-sdk/structures/login/_Login.scss b/src/skins/vector/css/matrix-react-sdk/structures/login/_Login.scss
index 90dd2c1e..30231b43 100644
--- a/src/skins/vector/css/matrix-react-sdk/structures/login/_Login.scss
+++ b/src/skins/vector/css/matrix-react-sdk/structures/login/_Login.scss
@@ -18,7 +18,6 @@ limitations under the License.
     width: 100%;
     height: 100%;
 
-    display: -ms-flexbox;
     display: flex;
     align-items: center;
     justify-content: center;
diff --git a/src/skins/vector/css/matrix-react-sdk/views/rooms/_MemberList.scss b/src/skins/vector/css/matrix-react-sdk/views/rooms/_MemberList.scss
index 9c1daa95..d87bced4 100644
--- a/src/skins/vector/css/matrix-react-sdk/views/rooms/_MemberList.scss
+++ b/src/skins/vector/css/matrix-react-sdk/views/rooms/_MemberList.scss
@@ -22,7 +22,6 @@ limitations under the License.
 
     flex: 1;
 
-    display: -ms-flexbox;
     display: flex;
 
     flex-direction: column;
diff --git a/src/skins/vector/css/matrix-react-sdk/views/rooms/_RoomHeader.scss b/src/skins/vector/css/matrix-react-sdk/views/rooms/_RoomHeader.scss
index 297a3f16..688b8a84 100644
--- a/src/skins/vector/css/matrix-react-sdk/views/rooms/_RoomHeader.scss
+++ b/src/skins/vector/css/matrix-react-sdk/views/rooms/_RoomHeader.scss
@@ -27,14 +27,12 @@ limitations under the License.
 
     align-items: center;
 
-    display: -ms-flexbox;
     display: flex;
 }
 
 .mx_RoomHeader_leftRow {
     margin-left: -2px;
 
-    -ms-flex-order: 1;
     order: 1;
 
     flex: 1;
@@ -43,7 +41,6 @@ limitations under the License.
 .mx_RoomHeader_spinner {
     height: 36px;
 
-    -ms-flex-order: 2;
     order: 2;
 
     padding-left: 12px;
@@ -60,7 +57,6 @@ limitations under the License.
     margin-top: -2px;
     text-align: center;
 
-    -ms-flex-order: 2;
     order: 2;
 
     cursor: pointer;
@@ -73,7 +69,6 @@ limitations under the License.
 }
 
 .mx_RoomHeader_cancelButton {
-    -ms-flex-order: 2;
     order: 2;
 
     cursor: pointer;
@@ -87,7 +82,6 @@ limitations under the License.
     background-color: $primary-bg-color;
     display: flex;
     align-items: center;
-    -ms-flex-order: 3;
     order: 3;
 }
 
diff --git a/src/skins/vector/css/matrix-react-sdk/views/rooms/_RoomPreviewBar.scss b/src/skins/vector/css/matrix-react-sdk/views/rooms/_RoomPreviewBar.scss
index 2114e01a..3814f9c0 100644
--- a/src/skins/vector/css/matrix-react-sdk/views/rooms/_RoomPreviewBar.scss
+++ b/src/skins/vector/css/matrix-react-sdk/views/rooms/_RoomPreviewBar.scss
@@ -24,7 +24,6 @@ limitations under the License.
 
     justify-content: center;
 
-    display: -ms-flexbox;
     display: flex;
 }
 
diff --git a/src/skins/vector/css/vector-web/structures/_LeftPanel.scss b/src/skins/vector/css/vector-web/structures/_LeftPanel.scss
index 030c5367..1ce10e51 100644
--- a/src/skins/vector/css/vector-web/structures/_LeftPanel.scss
+++ b/src/skins/vector/css/vector-web/structures/_LeftPanel.scss
@@ -17,7 +17,6 @@ limitations under the License.
 .mx_LeftPanel {
     position: relative;
 
-    display: -ms-flexbox;
     display: flex;
     flex-direction: column;
 }
@@ -35,7 +34,6 @@ limitations under the License.
 }
 
 .mx_LeftPanel .mx_RoomList_scrollbar {
-    -ms-flex-order: 1;
     order: 1;
 
     flex: 1 1 0;
@@ -49,7 +47,6 @@ limitations under the License.
 }
 
 .mx_LeftPanel .mx_BottomLeftMenu {
-    -ms-flex-order: 3;
     order: 3;
 
     border-top: 1px solid rgba(118, 207, 166, 0.2);
diff --git a/src/skins/vector/css/vector-web/structures/_RightPanel.scss b/src/skins/vector/css/vector-web/structures/_RightPanel.scss
index a76e5020..96e8698b 100644
--- a/src/skins/vector/css/vector-web/structures/_RightPanel.scss
+++ b/src/skins/vector/css/vector-web/structures/_RightPanel.scss
@@ -17,13 +17,11 @@ limitations under the License.
 .mx_RightPanel {
     position: relative;
 
-    display: -ms-flexbox;
     display: flex;
     flex-direction: column;
 }
 
 .mx_RightPanel_header {
-    -ms-flex-order: 1;
     order: 1;
 
     border-bottom: 1px solid $primary-hairline-color;
@@ -73,13 +71,11 @@ limitations under the License.
 .mx_RightPanel .mx_MemberList,
 .mx_RightPanel .mx_MemberInfo,
 .mx_RightPanel_blank {
-    -ms-flex-order: 2;
     order: 2;
     flex: 1 1 0;
 }
 
 .mx_RightPanel_footer {
-    -ms-flex-order: 3;
     order: 3;
 
     border-top: 1px solid $primary-hairline-color;
diff --git a/src/skins/vector/css/vector-web/structures/_RoomDirectory.scss b/src/skins/vector/css/vector-web/structures/_RoomDirectory.scss
index e2b65e68..f0d4c860 100644
--- a/src/skins/vector/css/vector-web/structures/_RoomDirectory.scss
+++ b/src/skins/vector/css/vector-web/structures/_RoomDirectory.scss
@@ -22,7 +22,6 @@ limitations under the License.
     margin-bottom: 12px;
     color: $primary-fg-color;
 
-    display: -ms-flexbox;
     display: flex;
 
     flex-direction: column;
@@ -31,7 +30,6 @@ limitations under the License.
 .mx_RoomDirectory_list {
     flex: 1;
 
-    display: -ms-flexbox;
     display: flex;
 
     flex-direction: column;
diff --git a/src/skins/vector/css/vector-web/views/globals/_GuestWarningBar.scss b/src/skins/vector/css/vector-web/views/globals/_GuestWarningBar.scss
index d9d3cb19..f5bdbaf9 100644
--- a/src/skins/vector/css/vector-web/views/globals/_GuestWarningBar.scss
+++ b/src/skins/vector/css/vector-web/views/globals/_GuestWarningBar.scss
@@ -18,7 +18,6 @@ limitations under the License.
     background-color: $accent-color;
     color: $accent-fg-color;
 
-    display: -ms-flexbox;
     display: flex;
     align-items: center;
 }
diff --git a/src/skins/vector/css/vector-web/views/globals/_MatrixToolbar.scss b/src/skins/vector/css/vector-web/views/globals/_MatrixToolbar.scss
index a425d8cd..5a0b23ae 100644
--- a/src/skins/vector/css/vector-web/views/globals/_MatrixToolbar.scss
+++ b/src/skins/vector/css/vector-web/views/globals/_MatrixToolbar.scss
@@ -18,7 +18,6 @@ limitations under the License.
     background-color: $accent-color;
     color: $accent-fg-color;
 
-    display: -ms-flexbox;
     display: flex;
     align-items: center;
 }