Mashlets have evolved into and replaced by Presto Apps, virtually everything you were able to do with a Mashlet you are now able to do with an App.
Tooling is provided to migrate 2.7 Mashlets to 3.0 Apps. 2.7 Basic Mashlets, these are the non-custom coded mashlets you would have created using Mashlet maker in 2.7, these can be converted into 3.0 Presto Basic Apps using the Migrate command, detailed here:
http://www.jackbe.com/prestodocs/v3.0/administration/migrateCmd.html
The topic of migrating 2.7 Custom Mashlet to 3.0 Custom Apps is covered here:
http://www.jackbe.com/prestodocs/v3.0/administration/migrateCustomMashlet.html#jbid10A5F0KI0Y4
The Migrate tool fully automates the migration of Basic Mashlets into Basic Apps with a single command. Custom Mashlets must be migrated individually using the Presto App Editor, some manual changes may be required to get your custom mashlets working in Presto3.0. Some of the issues you may hit when migrating your Custom Mashlets are discussed here:
http://www.jackbe.com/prestodocs/v3.0/administration/migrateCustomMashlet.html#jbid10A5G20L0HS
I haven't been back to the community in a bit, and wanted to upgrade my 2.7 to 3, including my custom mashlets.
If someone has a second, can they please give me an overview of what transitioned from mashlets? I do not seem to see them referenced in the design of 3.0. Thanks-