diff --git a/Firmware/Marlin_main.cpp b/Firmware/Marlin_main.cpp
index 1c8683cf..7d9ad5df 100644
--- a/Firmware/Marlin_main.cpp
+++ b/Firmware/Marlin_main.cpp
@@ -5932,10 +5932,31 @@ Sigma_Exit:
 			}
 		}
 		break;
-    case 204: // M204 acclereration S normal moves T filmanent only moves
+    case 204:
+      // M204 acclereration settings.
+      // Supporting old format: M204 S[normal moves] T[filmanent only moves]
+      // and new format:        M204 P[printing moves] R[filmanent only moves] T[travel moves] (as of now T is ignored)
       {
-        if(code_seen('S')) acceleration = code_value() ;
-        if(code_seen('T')) retract_acceleration = code_value() ;
+        if(code_seen('S')) {
+          // Legacy acceleration format. This format is used by the legacy Marlin, MK2 or MK3 firmware,
+          // and it is also generated by Slic3r to control acceleration per extrusion type
+          // (there is a separate acceleration settings in Slicer for perimeter, first layer etc).
+          acceleration = code_value();
+          // Interpret the T value as retract acceleration in the old Marlin format.
+          if(code_seen('T'))
+            retract_acceleration = code_value();
+        } else {
+          // New acceleration format, compatible with the upstream Marlin.
+          if(code_seen('P'))
+            acceleration = code_value();
+          if(code_seen('R'))
+            retract_acceleration = code_value();
+          if(code_seen('T')) {
+            // Interpret the T value as the travel acceleration in the new Marlin format.
+            //FIXME Prusa3D firmware currently does not support travel acceleration value independent from the extruding acceleration value.
+            // travel_acceleration = code_value();
+          }
+        }
       }
       break;
     case 205: //M205 advanced settings:  minimum travel speed S=while printing T=travel only,  B=minimum segment time X= maximum xy jerk, Z=maximum Z jerk