diff --git a/Changes b/Changes
index 72f687a4d..3b8e2d508 100644
--- a/Changes
+++ b/Changes
@@ -34,6 +34,8 @@ The contributors that suggested a given feature are shown in []. Thanks!
 
 ****  Fix std:: build error, bug1322.
 
+****  Change MODDUP errors to warnings, msg2588. [Marshal Qiao]
+
 
 * Verilator 3.924 2018-06-12
 
diff --git a/bin/verilator b/bin/verilator
index 2a6a45cc2..23de61cd8 100755
--- a/bin/verilator
+++ b/bin/verilator
@@ -3576,10 +3576,14 @@ correctly.
 
 =item MODDUP
 
-Error that a module has multiple definitions.  Generally this indicates a
+Warns that a module has multiple definitions.  Generally this indicates a
 coding error, or a mistake in a library file and it's good practice to have
-one module per file to avoid these issues.  For some gate level netlists
-duplicates are unavoidable, and this error may be disabled.
+one module per file (and only put each file once on the command line) to
+avoid these issues.  For some gate level netlists duplicates are sometimes
+unavoidable, and MODDUP should be disabled.
+
+Ignoring this warning will cause the more recent module definition to be
+discarded.
 
 =item MULTIDRIVEN
 
diff --git a/configure.ac b/configure.ac
index e24b8ce1f..0dd5aadf6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6,7 +6,8 @@
 
 #AC_INIT([Verilator],[#.### YYYY-MM-DD])
 #AC_INIT([Verilator],[#.### devel])
-AC_INIT([Verilator],[4.000 devel])
+AC_INIT([Verilator],[4.000 devel],[https://www.veripool.org/verilator],
+        [verilator],[https://www.veripool.org/verilator])
 # When releasing, also update header of Changes file
 # and commit using "devel release" or "Version bump" message
 
diff --git a/src/V3Error.h b/src/V3Error.h
index ecb12dce5..c0fad9f76 100644
--- a/src/V3Error.h
+++ b/src/V3Error.h
@@ -156,7 +156,7 @@ public:
     // Later -Werror- options may make more of these.
     bool pretendError() const { return ( m_e==ASSIGNIN || m_e==BLKANDNBLK
 					 || m_e==BLKLOOPINIT
-					 || m_e==IMPURE || m_e==MODDUP); }
+					 || m_e==IMPURE); }
     // Warnings to mention manual
     bool mentionManual() const { return ( m_e==EC_FATALSRC || m_e==SYMRSVDWORD
 					  || pretendError() ); }
diff --git a/test_regress/t/t_mod_dup_bad.pl b/test_regress/t/t_mod_dup_bad.pl
index 1ebee5d1a..92d6612c5 100755
--- a/test_regress/t/t_mod_dup_bad.pl
+++ b/test_regress/t/t_mod_dup_bad.pl
@@ -12,8 +12,8 @@ scenarios(vlt_all => 1);
 compile(
     fails => 1,
     expect =>
-'%Error-MODDUP: t/t_mod_dup_bad.v:\d+: Duplicate declaration of module: a
-%Error-MODDUP: t/t_mod_dup_bad.v:\d+: ... Location of original declaration
+'%Warning-MODDUP: t/t_mod_dup_bad.v:\d+: Duplicate declaration of module: a
+%Warning-MODDUP: t/t_mod_dup_bad.v:\d+: ... Location of original declaration
 .*
 %Error: Exiting due to.*',
     );