diff --git a/src/clientversion.h b/src/clientversion.h
--- a/src/clientversion.h
+++ b/src/clientversion.h
@@ -49,6 +49,8 @@
 extern const std::string CLIENT_BUILD;
 
 std::string FormatFullVersion();
+std::string FormatSubVersionUserAgent(const std::string &userAgent,
+                                      const std::vector<std::string> &comments);
 std::string FormatSubVersion(const std::string &name, int nClientVersion,
                              const std::vector<std::string> &comments);
 
diff --git a/src/clientversion.cpp b/src/clientversion.cpp
--- a/src/clientversion.cpp
+++ b/src/clientversion.cpp
@@ -60,14 +60,15 @@
 }
 
 /**
- * Format the subversion field according to BIP 14 spec
+ * Format the subversion field according to BIP 14 spec using given userAgent.
  * (https://github.com/bitcoin/bips/blob/master/bip-0014.mediawiki)
  */
-std::string FormatSubVersion(const std::string &name, int nClientVersion,
-                             const std::vector<std::string> &comments) {
+std::string
+FormatSubVersionUserAgent(const std::string &userAgent,
+                          const std::vector<std::string> &comments) {
     std::ostringstream ss;
     ss << "/";
-    ss << name << ":" << FormatVersion(nClientVersion);
+    ss << userAgent;
     if (!comments.empty()) {
         std::vector<std::string>::const_iterator it(comments.begin());
         ss << "(" << *it;
@@ -79,3 +80,14 @@
     ss << "/";
     return ss.str();
 }
+
+/**
+ * Format the subversion field according to BIP 14 spec
+ * (https://github.com/bitcoin/bips/blob/master/bip-0014.mediawiki)
+ */
+std::string FormatSubVersion(const std::string &name, int nClientVersion,
+                             const std::vector<std::string> &comments) {
+    std::ostringstream ss;
+    ss << name << ":" << FormatVersion(nClientVersion);
+    return FormatSubVersionUserAgent(ss.str(), comments);
+}
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -1852,6 +1852,25 @@
         std::string("/Test:0.9.99(comment1; Comment2; .,_?@-; )/"));
 }
 
+BOOST_AUTO_TEST_CASE(test_FormatSubVersionUserAgent) {
+    std::vector<std::string> comments;
+    comments.push_back(std::string("comment1"));
+    std::vector<std::string> comments2;
+    comments2.push_back(std::string("comment1"));
+    // Semicolon is discouraged but not forbidden by BIP-0014
+    comments2.push_back(SanitizeString(
+        std::string("Comment2; .,_?@-; !\"#$%&'()*+/<=>[]\\^`{|}~"),
+        SAFE_CHARS_UA_COMMENT));
+    BOOST_CHECK_EQUAL(
+        FormatSubVersionUserAgent("Test:0.9.99", std::vector<std::string>()),
+        std::string("/Test:0.9.99/"));
+    BOOST_CHECK_EQUAL(FormatSubVersionUserAgent("Test:0.9.99", comments),
+                      std::string("/Test:0.9.99(comment1)/"));
+    BOOST_CHECK_EQUAL(
+        FormatSubVersionUserAgent("Test:0.9.99", comments2),
+        std::string("/Test:0.9.99(comment1; Comment2; .,_?@-; )/"));
+}
+
 BOOST_AUTO_TEST_CASE(test_ParseFixedPoint) {
     int64_t amount = 0;
     BOOST_CHECK(ParseFixedPoint("0", 8, &amount));