diff --git a/libs/core/_locales/core-jsdoc-strings.json b/libs/core/_locales/core-jsdoc-strings.json
index 595da5d5..3cc86499 100644
--- a/libs/core/_locales/core-jsdoc-strings.json
+++ b/libs/core/_locales/core-jsdoc-strings.json
@@ -55,6 +55,7 @@
   "Buffer.getNumber": "Read a number in specified format from the buffer.",
   "Buffer.getUint8": "Reads an unsigned byte at a particular location",
   "Buffer.indexOf": "Return position of other buffer in current buffer",
+  "Buffer.isReadOnly": "Returns false when the buffer can be written to.",
   "Buffer.length": "Returns the length of a Buffer object.",
   "Buffer.rotate": "Rotate buffer left in place.\n\n\n\nstart. eg: -1",
   "Buffer.rotate|param|length": "number of elements in buffer. If negative, length is set as the buffer length minus",
diff --git a/libs/core/shims.d.ts b/libs/core/shims.d.ts
index 70d6f4c2..7199a1b2 100644
--- a/libs/core/shims.d.ts
+++ b/libs/core/shims.d.ts
@@ -950,6 +950,12 @@ declare interface Buffer {
     //% shim=BufferMethods::getUint8
     getUint8(off: int32): int32;
 
+    /**
+     * Returns false when the buffer can be written to.
+     */
+    //% shim=BufferMethods::isReadOnly
+    isReadOnly(): boolean;
+
     /**
      * Writes an unsigned byte at a particular location
      */
diff --git a/package.json b/package.json
index ce4b3d9b..fa7f640b 100644
--- a/package.json
+++ b/package.json
@@ -46,7 +46,7 @@
     "typescript": "2.6.1"
   },
   "dependencies": {
-    "pxt-common-packages": "6.17.1",
-    "pxt-core": "5.31.2"
+    "pxt-common-packages": "6.18.2",
+    "pxt-core": "5.31.8"
   }
 }