The new client has a protection against debuggers which causes the client to crash upon debug attachment.

Two ways:

1. Open Olly, go to 004BE7F7, change JZ SHORT 004BE818 to JMP SHORT 004BE818.

or

2. Open the client using an Hex editor. Go to 004BE7F7 and change 74 to EB.

Save and you are good to go.