diff --git a/pom.xml b/pom.xml
index 54cb62edd..b367969a7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
     <artifactId>mariadb-java-client</artifactId>
     <packaging>jar</packaging>
     <name>mariadb-java-client</name>
-    <version>1.2.0</version>
+    <version>1.2.1-SNAPSHOT</version>
     <description>JDBC driver for MariaDB and MySQL</description>
     <url>https://mariadb.com/kb/en/mariadb/about-mariadb-connector-j/</url>
     <properties>
diff --git a/src/main/java/org/mariadb/jdbc/Driver.java b/src/main/java/org/mariadb/jdbc/Driver.java
index 69b875f88..9ec6b3547 100644
--- a/src/main/java/org/mariadb/jdbc/Driver.java
+++ b/src/main/java/org/mariadb/jdbc/Driver.java
@@ -92,6 +92,8 @@ public Connection connect(final String url, final Properties props) throws SQLEx
         log.debug("Connecting to: " + url);
         try {
             JDBCUrl jdbcUrl = JDBCUrl.parse(url, props);
+            //
+            if (jdbcUrl == null) return null;
             if (jdbcUrl.getHostAddresses() == null) {
                 log.info("MariaDB connector : missing Host address");
                 return null;
diff --git a/src/main/java/org/mariadb/jdbc/JDBCUrl.java b/src/main/java/org/mariadb/jdbc/JDBCUrl.java
index 439ef85fa..19d5ad502 100644
--- a/src/main/java/org/mariadb/jdbc/JDBCUrl.java
+++ b/src/main/java/org/mariadb/jdbc/JDBCUrl.java
@@ -116,7 +116,7 @@ protected JDBCUrl(String database, List<HostAddress> addresses, Options options,
 
     static boolean acceptsURL(String url) {
         return (url != null) &&
-                (url.startsWith("jdbc:mariadb://") || url.startsWith("jdbc:mysql://"));
+                (url.startsWith("jdbc:mariadb:") || url.startsWith("jdbc:mysql:"));
 
     }
 
@@ -141,7 +141,7 @@ public static JDBCUrl parse(final String url, Properties prop) {
                 }
             }
         }
-        throw new IllegalArgumentException("Invalid connection URL url " + url);
+        return null;
     }
 
     public void parseUrl(String url) {
diff --git a/src/main/java/org/mariadb/jdbc/Version.java b/src/main/java/org/mariadb/jdbc/Version.java
index 7b983c1af..c1cc7226f 100644
--- a/src/main/java/org/mariadb/jdbc/Version.java
+++ b/src/main/java/org/mariadb/jdbc/Version.java
@@ -1,10 +1,10 @@
 package org.mariadb.jdbc;
 
 public final class Version {
-    public static final String version = "1.2.0";
+    public static final String version = "1.2.1-SNAPSHOT";
     public static final int majorVersion = 1;
     public static final int minorVersion = 2;
-    public static final int patchVersion = 0;
-    public static final String qualifier = "";
+    public static final int patchVersion = 1;
+    public static final String qualifier = "SNAPSHOT";
 
 }
\ No newline at end of file
diff --git a/src/main/java/org/mariadb/jdbc/internal/mysql/listener/impl/MastersSlavesListener.java b/src/main/java/org/mariadb/jdbc/internal/mysql/listener/impl/MastersSlavesListener.java
index 519e6c391..2fa7cd8dd 100644
--- a/src/main/java/org/mariadb/jdbc/internal/mysql/listener/impl/MastersSlavesListener.java
+++ b/src/main/java/org/mariadb/jdbc/internal/mysql/listener/impl/MastersSlavesListener.java
@@ -333,7 +333,6 @@ public void switchReadOnlyConnection(Boolean mustBeReadOnly) throws QueryExcepti
                             syncConnection(this.masterProtocol, this.secondaryProtocol);
 
                             currentProtocol = this.secondaryProtocol;
-                            setSessionReadOnly(true);
 
                             log.trace("current connection is now secondary");
                             return;
@@ -612,7 +611,7 @@ public void run() {
     }
 
     public void checkIfTypeHaveChanged(SearchFilter searchFilter) throws QueryException {
-        if (masterProtocol.ping()) {
+        if (masterProtocol != null && masterProtocol.ping()) {
             log.trace("PingLoop master ping ok");
         }
     }
diff --git a/src/test/java/org/mariadb/jdbc/JdbcParserTest.java b/src/test/java/org/mariadb/jdbc/JdbcParserTest.java
index ce4ef85f2..4e15a2788 100644
--- a/src/test/java/org/mariadb/jdbc/JdbcParserTest.java
+++ b/src/test/java/org/mariadb/jdbc/JdbcParserTest.java
@@ -79,12 +79,8 @@ public void testJDBCParserSimpleIPv4basic() {
     }
     @Test
     public void testJDBCParserSimpleIPv4basicError() {
-        try {
-            JDBCUrl.parse(null);
-            Assert.fail();
-        }catch (IllegalArgumentException e) {
-            Assert.assertTrue(true);
-        }
+        JDBCUrl jdbcUrl = JDBCUrl.parse(null);
+        Assert.assertTrue(jdbcUrl == null);
     }
     @Test
     public void testJDBCParserSimpleIPv4basicwithoutDatabase() {
@@ -157,21 +153,11 @@ public void testJDBCParserParameter() {
         Assert.assertTrue(new HostAddress("slave1", 3308, "slave").equals(jdbcUrl.getHostAddresses().get(2)));
     }
 
-    @Test
-    public void testJDBCParserParameterError() {
-        try {
-            JDBCUrl.parse(null);
-            Assert.fail();
-        }catch (IllegalArgumentException e) {
-            Assert.assertTrue(true);
-        }
-    }
-
     @Test
     public void testJDBCParserParameterErrorEqual() {
         String url = "jdbc:mysql://address=(type=)(port=3306)(host=master1),address=(port=3307)(type=master)(host=master2),address=(type=slave)(host=slave1)(port=3308)/database?user=greg&password=pass";
         try {
-            JDBCUrl.parse(null);
+            JDBCUrl.parse(url);
             Assert.fail();
         }catch (IllegalArgumentException e) {
             Assert.assertTrue(true);
@@ -223,4 +209,14 @@ public void testJDBCParserHAModeLoadAurora() {
         Assert.assertTrue(jdbc.getHaMode().equals(UrlHAMode.AURORA));
     }
 
+    /**
+     * CONJ-167 : Driver is throwing IllegalArgumentException instead of returning null
+     */
+    @Test
+    public void checkOtherDriverCompatibility() {
+        String url = "jdbc:h2:mem:RZM;DB_CLOSE_DELAY=-1";
+        JDBCUrl jdbc = JDBCUrl.parse(url);
+        Assert.assertTrue(jdbc == null);
+    }
+
 }
diff --git a/src/test/resources/logging.properties b/src/test/resources/logging.properties
deleted file mode 100644
index f02449094..000000000
--- a/src/test/resources/logging.properties
+++ /dev/null
@@ -1,6 +0,0 @@
-handlers = java.util.logging.ConsoleHandler
-java.util.logging.ConsoleHandler.level = FINE
-java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter
-# Pattern works since Java 7
-java.util.logging.SimpleFormatter.format = [%1$tc] %4$s: %2$s - %5$s %6$s%n
-org.mariadb.jdbc.level=FINE
\ No newline at end of file