diff --git a/xep-0264.xml b/xep-0264.xml
index 79cee04e..d06d18e2 100644
--- a/xep-0264.xml
+++ b/xep-0264.xml
@@ -168,7 +168,7 @@ file being offered (name, size, and date). There currently is no way to provide
   <p>The inclusion of an image thumbnail may leak information about a transfer
 otherwise taking place on an e2e encrypted file transfer stream. A client MAY
 wish to not include a thumbnail.</p>
-  <p>A client MUST not rely on the values specified for the width and height of a thumbnail to allocate a bitmap data buffer for the thumbnail, to prevent possible DoS attacks. Also a client SHOULD apply implementation-specific limits on the thumbnails, if using these values to pepare a UI element for the thumbnail image, of f.ex. 128x128 pixels, values exceeding theese would then be truncated and the thumbnail image scaled down when received.</p>
+  <p>A client MUST NOT rely on the values specified for the width and height of a thumbnail to allocate a bitmap data buffer for the thumbnail, to prevent possible DoS attacks. Also a client SHOULD apply implementation-specific limits on the thumbnails, if using these values to pepare a UI element for the thumbnail image, of f.ex. 128x128 pixels, values exceeding theese would then be truncated and the thumbnail image scaled down when received.</p>
 </section1>
 <section1 topic='IANA Considerations' anchor='iana'>
   <p>This document requires no interaction with &IANA;.</p>