The Model Builder service will be upgraded on Friday, March 11, 2016, and will no longer support release version 2015.3 of InfraWorks 360. This means that if you are using InfraWorks 360 release version 2015.3, the Model Builder service will no longer work for you beginning March 11, 2016. (For your reference, release version 2015.3 is also known as the December 2014 release of InfraWorks 360.)
This will not affect models that you have already created with the Model Builder, but you will be unable to create new models with the Model Builder if you are using the 2015.3 release version of InfraWorks 360 on or after March 11, 2016. To ensure that you can continue to use the Model Builder, make sure that you upgrade to a more recent release version of InfraWorks 360. You can upgrade to a more recent release of InfraWorks 360 after March 11, 2016, but we recommend that you do so in advance.
If you forget to upgrade to a more recent release of InfraWorks 360 — don’t worry! Beginning March 11, 2016, InfraWorks 360 will push you the following notification (shown in the image below) when you try to use the Model Builder with the 2015.3 release version of InfraWorks 360. You can follow the instructions in the notification to resume using the Model Builder service.