A new release of the OT, containing the most up to date information on observatory capabilities, will be announced with every observing cycle in the call for proposals. The link to download the OT will be updated on the OT page of the ALMA Science Portal.  It is important that you use the most up to date version for your new proposals.  

If you are running the wrong version of the OT, it will not be possible to submit your proposal or observing program!

If there is an update during the call, the OT will notify you to download the new patch unless you are using the tarball version. There will also be a news item posted on the ALMA Science Portal.