diff --git a/NEWS.md b/NEWS.md
index 0e0e7065..7cb94d34 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 # httr 1.0.0.9000
 
+* fix for 'progress callback must return boolean' warning
+
 # httr 1.0.0
 
 * httr no longer uses the RCurl package. Instead it uses the curl package, 
diff --git a/R/progress.R b/R/progress.R
index c51a67b7..720eb9de 100644
--- a/R/progress.R
+++ b/R/progress.R
@@ -36,7 +36,7 @@ progress_bar <- function(type) {
     if (total == 0 && now == 0) {
       bar <<- NULL
       first <<- TRUE
-      return()
+      return(TRUE)
     }
 
     if (total == 0) {
@@ -53,7 +53,7 @@ progress_bar <- function(type) {
       setTxtProgressBar(bar, now)
     }
 
-    0L
+    TRUE
   }
 
   show_progress