diff --git a/internal/internal.go b/internal/internal.go
index f1d0efd1c..8907e4e3c 100644
--- a/internal/internal.go
+++ b/internal/internal.go
@@ -18,7 +18,7 @@ import "time"
 
 // UserAgent is the user agent to be added to the outgoing
 // requests from the exporters.
-const UserAgent = "opencensus-go-v0.1.0"
+const UserAgent = "opencensus-go-v0.4.0"
 
 // MonotonicEndTime returns the end time at present
 // but offset from start, monotonically.