diff --git a/src/skins/vector/css/_common.scss b/src/skins/vector/css/_common.scss
index 6a62385535..5e0b902a85 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;
-    -moz-transition: opacity 0.2s ease-in-out;
     -ms-transition: opacity 0.2s ease-in-out;
     -o-transition: opacity 0.2s ease-in-out;
 }
@@ -127,7 +126,6 @@ textarea {
     width: 100%;
     height: 100%;
 
-    display: -moz-box;
     display: -ms-flexbox;
     display: flex;
     align-items: 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 6c769a3bdd..2fb1131d09 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 {
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
 
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 61eb017058..72f1feffe9 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: -moz-box;
     display: -ms-flexbox;
     display: flex;
 
@@ -38,7 +37,6 @@ limitations under the License.
 }
 
 .mx_MatrixToolbar {
-    -moz-box-ordinal-group: 1;
     -ms-flex-order: 1;
     order: 1;
 
@@ -46,7 +44,6 @@ limitations under the License.
 }
 
 .mx_GuestWarningBar {
-    -moz-box-ordinal-group: 1;
     -ms-flex-order: 1;
     order: 1;
 
@@ -61,11 +58,9 @@ limitations under the License.
     width: 100%;
     height: 100%;
 
-    display: -moz-box;
     display: -ms-flexbox;
     display: flex;
 
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
 
@@ -73,7 +68,6 @@ limitations under the License.
 }
 
 .mx_MatrixChat .mx_LeftPanel {
-    -moz-box-ordinal-group: 1;
     -ms-flex-order: 1;
     order: 1;
 
@@ -87,7 +81,6 @@ limitations under the License.
 }
 
 .mx_MatrixChat .mx_MatrixChat_middlePanel {
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
 
@@ -113,13 +106,11 @@ limitations under the License.
      * point, but instead we fudge it and make the middlePanel
      * flex itself.
      */
-    display: -moz-box;
     display: -ms-flexbox;
     display: flex;
 }
 
 .mx_MatrixChat .mx_RightPanel {
-    -moz-box-ordinal-group: 3;
     -ms-flex-order: 3;
     order: 3;
 
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 ed81849776..b3f724d83d 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 {
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
 
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 dc668236b8..6a5db95a59 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: -moz-box;
     display: -ms-flexbox;
     display: flex;
     width: 100%;
@@ -27,7 +26,6 @@ limitations under the License.
 }
 
 .mx_RoomView .mx_RoomHeader {
-    -moz-box-ordinal-group: 1;
     -ms-flex-order: 1;
     order: 1;
 
@@ -47,8 +45,6 @@ limitations under the License.
     padding-right: 12px;
     margin-left: -12px;
 
-    -moz-border-radius-topleft: 10px;
-    -moz-border-radius-topright: 10px;
     border-top-left-radius: 10px;
     border-top-right-radius: 10px;
 
@@ -69,7 +65,6 @@ limitations under the License.
 }
 
 .mx_RoomView_auxPanel {
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
 
@@ -85,13 +80,11 @@ limitations under the License.
 }
 
 .mx_RoomView_topUnreadMessagesBar {
-    -moz-box-ordinal-group: 3;
     -ms-flex-order: 3;
     order: 3;
 }
 
 .mx_RoomView_messagePanel {
-    -moz-box-ordinal-group: 4;
     -ms-flex-order: 4;
     order: 4;
 
@@ -108,7 +101,6 @@ limitations under the License.
 
     min-height: 100%;
 
-    display: -moz-box;
     display: -ms-flexbox;
     display: flex;
 
@@ -141,7 +133,6 @@ limitations under the License.
 }
 
 .mx_RoomView_invitePrompt {
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
 
@@ -170,7 +161,6 @@ hr.mx_RoomView_myReadMarker {
 }
 
 .mx_RoomView_statusArea {
-    -moz-box-ordinal-group: 5;
     -ms-flex-order: 5;
     order: 5;
 
@@ -231,7 +221,6 @@ hr.mx_RoomView_myReadMarker {
 }
 
 .mx_RoomView .mx_MessageComposer {
-    -moz-box-ordinal-group: 6;
     -ms-flex-order: 6;
     order: 6;
 
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 2c62a4eceb..d190e32c3a 100644
--- a/src/skins/vector/css/matrix-react-sdk/structures/_UserSettings.scss
+++ b/src/skins/vector/css/matrix-react-sdk/structures/_UserSettings.scss
@@ -20,14 +20,12 @@ limitations under the License.
     margin-left: auto;
     margin-right: auto;
 
-    display: -moz-box;
     display: -ms-flexbox;
     display: flex;
     flex-direction: column;
 }
 
 .mx_UserSettings .mx_RoomHeader {
-    -moz-box-ordinal-group: 1;
     -ms-flex-order: 1;
     order: 1;
 
@@ -35,7 +33,6 @@ limitations under the License.
 }
 
 .mx_UserSettings_body {
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
 
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 332f313f33..90dd2c1e2d 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: -moz-box;
     display: -ms-flexbox;
     display: flex;
     align-items: 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 403de7f945..9c1daa95b4 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: -moz-box;
     display: -ms-flexbox;
     display: flex;
 
diff --git a/src/skins/vector/css/matrix-react-sdk/views/rooms/_MessageComposer.scss b/src/skins/vector/css/matrix-react-sdk/views/rooms/_MessageComposer.scss
index a4549c0f8e..5ecb344106 100644
--- a/src/skins/vector/css/matrix-react-sdk/views/rooms/_MessageComposer.scss
+++ b/src/skins/vector/css/matrix-react-sdk/views/rooms/_MessageComposer.scss
@@ -105,7 +105,6 @@ limitations under the License.
     border: 0px;
     resize: none;
     outline: none;
-    -moz-box-shadow: none;
     box-shadow: none;
     color: $primary-fg-color;
     background-color: $primary-bg-color;
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 73327ea6a0..297a3f1659 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
@@ -27,7 +27,6 @@ limitations under the License.
 
     align-items: center;
 
-    display: -moz-box;
     display: -ms-flexbox;
     display: flex;
 }
@@ -35,7 +34,6 @@ limitations under the License.
 .mx_RoomHeader_leftRow {
     margin-left: -2px;
 
-    -moz-box-ordinal-group: 1;
     -ms-flex-order: 1;
     order: 1;
 
@@ -45,7 +43,6 @@ limitations under the License.
 .mx_RoomHeader_spinner {
     height: 36px;
 
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
 
@@ -63,7 +60,6 @@ limitations under the License.
     margin-top: -2px;
     text-align: center;
 
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
 
@@ -77,7 +73,6 @@ limitations under the License.
 }
 
 .mx_RoomHeader_cancelButton {
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
 
@@ -92,7 +87,6 @@ limitations under the License.
     background-color: $primary-bg-color;
     display: flex;
     align-items: center;
-    -moz-box-ordinal-group: 3;
     -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 0d030ad774..2114e01a8e 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: -moz-box;
     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 36a1e2988d..030c53677f 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: -moz-box;
     display: -ms-flexbox;
     display: flex;
     flex-direction: column;
@@ -36,7 +35,6 @@ limitations under the License.
 }
 
 .mx_LeftPanel .mx_RoomList_scrollbar {
-    -moz-box-ordinal-group: 1;
     -ms-flex-order: 1;
     order: 1;
 
@@ -51,7 +49,6 @@ limitations under the License.
 }
 
 .mx_LeftPanel .mx_BottomLeftMenu {
-    -moz-box-ordinal-group: 3;
     -ms-flex-order: 3;
     order: 3;
 
diff --git a/src/skins/vector/css/vector-web/structures/_RightPanel.scss b/src/skins/vector/css/vector-web/structures/_RightPanel.scss
index 000d36b31b..a76e5020bc 100644
--- a/src/skins/vector/css/vector-web/structures/_RightPanel.scss
+++ b/src/skins/vector/css/vector-web/structures/_RightPanel.scss
@@ -17,14 +17,12 @@ limitations under the License.
 .mx_RightPanel {
     position: relative;
 
-    display: -moz-box;
     display: -ms-flexbox;
     display: flex;
     flex-direction: column;
 }
 
 .mx_RightPanel_header {
-    -moz-box-ordinal-group: 1;
     -ms-flex-order: 1;
     order: 1;
 
@@ -75,14 +73,12 @@ limitations under the License.
 .mx_RightPanel .mx_MemberList,
 .mx_RightPanel .mx_MemberInfo,
 .mx_RightPanel_blank {
-    -moz-box-ordinal-group: 2;
     -ms-flex-order: 2;
     order: 2;
     flex: 1 1 0;
 }
 
 .mx_RightPanel_footer {
-    -moz-box-ordinal-group: 3;
     -ms-flex-order: 3;
     order: 3;
 
diff --git a/src/skins/vector/css/vector-web/structures/_RoomDirectory.scss b/src/skins/vector/css/vector-web/structures/_RoomDirectory.scss
index c80a8d8fc5..e2b65e68ec 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: -moz-box;
     display: -ms-flexbox;
     display: flex;
 
@@ -32,7 +31,6 @@ limitations under the License.
 .mx_RoomDirectory_list {
     flex: 1;
 
-    display: -moz-box;
     display: -ms-flexbox;
     display: flex;
 
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 2141f3a8ad..d9d3cb193c 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: -moz-box;
     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 9e21bcb1f2..a425d8cde2 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: -moz-box;
     display: -ms-flexbox;
     display: flex;
     align-items: center;