First, be sure to read :dpy_docs:`discord.py's migration guide <migrating.html>` as that covers all of the changes to discord.py that will affect the migration process
V3 makes Red a package that is installed with pip. Please
keep this in mind when writing cogs as this affects how imports
should be done (for example, to import pagify in V2, one
would do from .utils.chat_formatting import pagify; in
V3, this becomes from redbot.core.utils.chat_formatting import pagify)
V3 makes cogs into packages. See :doc:`/guide_cog_creation` for more on how to create packages for V3.
Config is V3's replacement for dataIO. Instead of fiddling with
creating config directories and config files as was done in V2, V3's
Config handles that whilst allowing for easy storage of settings on a
per-server/member/user/role/channel or global basis. Be sure to check
out :doc:`/framework_config` for the API docs for Config as well as a
tutorial on using Config.
Bank in V3 has been split out from Economy. V3 introduces the ability to have a global bank as well as the ability to change the bank name and the name of the currency. Be sure to checkout :doc:`/framework_bank` for more on Bank
V3 introduces Mod Log as an API, thus allowing for cogs to add custom case types that will appear in a server's mod log channel. Be sure to checkout :doc:`/framework_modlog` for more on Mod Log`