On January 29, in a security notice, Canonical published details about OTR vulnerabilities in its Ubuntu 12.04 LTS (Precise Pangolin) operating system.
According to the company, applications using the OTR secure chat protocol could have been made to expose sensitive information over the network.
In order to fix the problem, an update had to be released, which disables the OTR v1 protocol to prevent protocol downgrade attacks.
For a more detailed description of the problems, you can see Canonical's security notification.
The security flaws can be fixed if you upgrade your system(s) to the latest libotr2 specific to each distribution. To apply the update, run the Update Manager application.
In general, a standard system update will make all the necessary changes. A system restart will not be necessary to implement them.