I just upgraded to the latest beta and had it automatically upgrade my test project. I created a new workflow scenario, but when I went to use the web recorder I received the following error message in the console: 0 WARN com.thoughtworks.twist.messaging.RemoteSession – EXCEPTION, please implement com.thoughtworks.twist.messaging.RemoteSession.exceptionCaught() for proper handling:org.apache.mina.filter.codec.ProtocolDecoderException: org.apache.mina.common.BufferDataException: java.io.InvalidClassException: failed to read class descriptor (Hexdump: 00 00 03 65 AC ED 00 05 73 72 01 00 34 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 6D 65 73 73 61 67 69 6E 67 2E 65 76 65 6E 74 2E 52 65 63 6F 72 64 69 6E 67 49 6E 66 6F 78 72 01 00 34 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 6D 65 73 73 61 67 69 6E 67 2E 65 76 65 6E 74 2E 41 62 73 74 72 61 63 74 45 76 65 6E 74 78 70 76 72 01 00 44 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 6D 65 73 73 61 67 69 6E 67 2E 73 65 72 76 69 63 65 2E 72 65 6D 6F 74 65 2E 52 65 6D 6F 74 65 50 72 6F 63 65 73 73 53 65 72 76 69 63 65 78 70 74 00 08 73 65 6C 65 6E 69 75 6D 73 72 01 00 24 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 63 6F 72 65 2E 4C 69 73 74 49 74 65 6D 78 70 74 00 16 23 73 65 6C 65 63 74 20 62 75 69 6C 64 69 6E 67 20 22 42 43 4D 22 74 00 15 73 65 6C 65 63 74 20 62 75 69 6C 64 69 6E 67 20 22 42 43 4D 22 73 72 01 00 24 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 63 6F 72 65 2E 53 65 6E 74 65 6E 63 65 78 70 73 72 01 00 13 6A 61 76 61 2E 75 74 69 6C 2E 41 72 72 61 79 4C 69 73 74 78 70 00 00 00 07 77 04 00 00 00 0A 73 72 01 00 2A 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 63 6F 72 65 2E 66 72 61 67 6D 65 6E 74 73 2E 57 6F 72 64 78 72 01 00 36 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 63 6F 72 65 2E 66 72 61 67 6D 65 6E 74 73 2E 41 62 73 74 72 61 63 74 46 72 61 67 6D 65 6E 74 78 70 74 00 06 73 65 6C 65 63 74 73 72 01 00 30 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 63 6F 72 65 2E 66 72 61 67 6D 65 6E 74 73 2E 57 68 69 74 65 73 70 61 63 65 78 71 00 7E 00 0F 74 00 01 20 73 71 00 7E 00 0E 74 00 08 62 75 69 6C 64 69 6E 67 73 71 00 7E 00 12 74 00 01 20 73 72 01 00 30 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 63 6F 72 65 2E 66 72 61 67 6D 65 6E 74 73 2E 53 74 61 72 74 51 75 6F 74 65 78 71 00 7E 00 0F 74 00 01 22 73 72 01 00 2F 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 63 6F 72 65 2E 66 72 61 67 6D 65 6E 74 73 2E 50 61 72 61 6D 65 74 65 72 78 71 00 7E 00 0F 74 00 03 42 43 4D 73 72 01 00 2E 63 6F 6D 2E 74 68 6F 75 67 68 74 77 6F 72 6B 73 2E 74 77 69 73 74 2E 63 6F 72 65 2E 66 72 61 67 6D 65 6E 74 73 2E 45 6E 64 51 75 6F 74 65 78 71 00 7E 00 0F 71 00 7E 00 1B 78 73 72 01 00 0C 6A 61 76 61 2E 69 6F 2E 46 69 6C 65 78 70 74 00 44 43 3A 5C 50 72 6F 67 72 61 6D 20 46 69 6C 65 73 5C 74 77 69 73 74 5C 77 6F 72 6B 73 70 61 63 65 5C 56 53 4D 5C 73 63 65 6E 61 72 69 6F 73 5C 41 64 64 42 6F 78 54 6F 48 69 65 72 61 72 63 68 79 2E 73 63 6E 77 02 00 5C 78) at org.apache.mina.filter.codec.ProtocolCodecFilter.messageReceived(ProtocolCodecFilter.java:180) at org.apache.mina.common.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:405) at org.apache.mina.common.DefaultIoFilterChain.access$1200(DefaultIoFilterChain.java:40) at org.apache.mina.common.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:823) at org.apache.mina.common.DefaultIoFilterChain$HeadFilter.messageReceived(DefaultIoFilterChain.java:607) at org.apache.mina.common.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:405) at org.apache.mina.common.DefaultIoFilterChain.fireMessageReceived(DefaultIoFilterChain.java:399) at org.apache.mina.common.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:425) at org.apache.mina.common.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:387) at org.apache.mina.common.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:379) at org.apache.mina.common.AbstractPollingIoProcessor.access$400(AbstractPollingIoProcessor.java:43) at org.apache.mina.common.AbstractPollingIoProcessor$Worker.run(AbstractPollingIoProcessor.java:678) at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:51) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source)Caused by: org.apache.mina.common.BufferDataException: java.io.InvalidClassException: failed to read class descriptor at org.apache.mina.common.AbstractIoBuffer.getObject(AbstractIoBuffer.java:1596) at org.apache.mina.filter.codec.serialization.ObjectSerializationDecoder.doDecode(ObjectSerializationDecoder.java:93) at org.apache.mina.filter.codec.CumulativeProtocolDecoder.decode(CumulativeProtocolDecoder.java:145) at org.apache.mina.filter.codec.ProtocolCodecFilter.messageReceived(ProtocolCodecFilter.java:170) ... 15 moreCaused by: java.io.InvalidClassException: failed to read class descriptor at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source) at java.io.ObjectInputStream.readClassDesc(Unknown Source) at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at java.io.ObjectInputStream.readObject0(Unknown Source) at java.io.ObjectInputStream.defaultReadFields(Unknown Source) at java.io.ObjectInputStream.readSerialData(Unknown Source) at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at java.io.ObjectInputStream.readObject0(Unknown Source) at java.io.ObjectInputStream.defaultReadFields(Unknown Source) at java.io.ObjectInputStream.readSerialData(Unknown Source) at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at java.io.ObjectInputStream.readObject0(Unknown Source) at java.io.ObjectInputStream.readObject(Unknown Source) at org.apache.mina.common.AbstractIoBuffer.getObject(AbstractIoBuffer.java:1594) ... 18 moreCaused by: java.lang.ClassNotFoundException: com.thoughtworks.twist.core.Sentence at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClassInternal(Unknown Source) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Unknown Source) at org.apache.mina.common.AbstractIoBuffer$3.readClassDescriptor(AbstractIoBuffer.java:1575) ... 32 more Note: the Twist project has been configured with Firefox as the browser. Let me know if you need any more details. Thanks