diff --git a/README.md b/README.md
index 80e25fe..cdf9e20 100644
--- a/README.md
+++ b/README.md
@@ -42,7 +42,7 @@ This repository contains a [Racket](http://racket-lang.org/) package,
 
 ## Compiling and running the code
 
-You will need Racket version 6.2.x or later.
+You will need Racket version 6.3 or later.
 
 Once you have Racket installed, run
 
diff --git a/prospect-monolithic/drivers/tcp.rkt b/prospect-monolithic/drivers/tcp.rkt
index a253a64..936fd7d 100644
--- a/prospect-monolithic/drivers/tcp.rkt
+++ b/prospect-monolithic/drivers/tcp.rkt
@@ -1,9 +1,9 @@
 #lang racket/base
 
 (require racket/match)
+(require racket/exn)
 (require (prefix-in tcp: racket/tcp))
 (require (only-in racket/port read-bytes-avail!-evt))
-(require "../../prospect/exn-util.rkt")
 (require "../main.rkt")
 (require "../demand-matcher.rkt")
 
diff --git a/prospect-monolithic/trace/stderr.rkt b/prospect-monolithic/trace/stderr.rkt
index 2a01097..b57626b 100644
--- a/prospect-monolithic/trace/stderr.rkt
+++ b/prospect-monolithic/trace/stderr.rkt
@@ -5,8 +5,8 @@
 (require racket/set)
 (require racket/match)
 (require racket/pretty)
+(require racket/exn)
 (require (only-in racket/string string-join))
-(require "../../prospect/exn-util.rkt")
 (require "../core.rkt")
 (require "../../prospect/trace.rkt")
 (require "../mux.rkt")
diff --git a/prospect/drivers/tcp.rkt b/prospect/drivers/tcp.rkt
index 7d6f015..d92ab06 100644
--- a/prospect/drivers/tcp.rkt
+++ b/prospect/drivers/tcp.rkt
@@ -1,9 +1,9 @@
 #lang racket/base
 
 (require racket/match)
+(require racket/exn)
 (require (prefix-in tcp: racket/tcp))
 (require (only-in racket/port read-bytes-avail!-evt))
-(require "../exn-util.rkt")
 (require "../main.rkt")
 (require "../demand-matcher.rkt")
 
diff --git a/prospect/exn-util.rkt b/prospect/exn-util.rkt
deleted file mode 100644
index 17e23ed..0000000
--- a/prospect/exn-util.rkt
+++ /dev/null
@@ -1,8 +0,0 @@
-#lang racket/base
-
-(provide exn->string)
-
-(define (exn->string exn)
-  (parameterize ([current-error-port (open-output-string)])
-    ((error-display-handler) (exn-message exn) exn)
-    (get-output-string (current-error-port))))
diff --git a/prospect/pretty.rkt b/prospect/pretty.rkt
index bf52cf6..f50cb19 100644
--- a/prospect/pretty.rkt
+++ b/prospect/pretty.rkt
@@ -5,14 +5,14 @@
 
          prospect-pretty-print->string
 
-         exn->string ;; required from exn-util.rkt
+         exn->string ;; required from racket/exn
          string-indent
          indented-port-output)
 
 (require racket/generic)
 (require racket/pretty)
+(require racket/exn)
 (require (only-in racket/string string-join string-split))
-(require "exn-util.rkt")
 (require "route.rkt")
 
 (define-generics prospect-pretty-printable
diff --git a/prospect/trace/stderr.rkt b/prospect/trace/stderr.rkt
index ad26bf6..8011e63 100644
--- a/prospect/trace/stderr.rkt
+++ b/prospect/trace/stderr.rkt
@@ -5,8 +5,8 @@
 (require racket/set)
 (require racket/match)
 (require racket/pretty)
+(require racket/exn)
 (require (only-in racket/string string-join))
-(require "../exn-util.rkt")
 (require "../core.rkt")
 (require "../trace.rkt")
 (require "../mux.rkt")