diff --git a/src/index.coffee b/src/index.coffee
index b59bfe4..616cf56 100644
--- a/src/index.coffee
+++ b/src/index.coffee
@@ -13,15 +13,33 @@ handleRequest = ({ request }) ->
 
 handlePUT = (request) ->
   url = new URL request.url
+  # Start from the highest version number
+  valid = false
   if url.searchParams.has "v2"
     valid = await verifySignatureV2 url.searchParams.get("v2"), url, request
-    return verifyFailure() unless valid
+  else if url.searchParams.has "v"
+    valid = await verifySignatureV1 url.searchParams.get("v"), url, request
+
+  unless valid
+    return verifyFailure()
+
   return new Response "Valid"
 
 verifyFailure = ->
   return new Response "Invalid signature",
     status: 403
 
+verifySignatureV1 = (sig, url, request) ->
+  content_length = request.headers.get "Content-Length"
+  if not content_length?
+    return false
+
+  sign_str = url.pathname[1..] + " " + content_length
+  local_sig = await crypto.HMAC_SHA256 crypto.utf8Bytes(config.xmpp_secret), sign_str
+  local_sig = crypto.hex local_sig
+
+  return local_sig is sig
+
 verifySignatureV2 = (sig, url, request) ->
   content_length = request.headers.get "Content-Length"
   content_type = request.headers.get "Content-Type"