This tutorial is for updating from Akairo v7 to v9.
Many changes were introduced in v8 so hopefully this guide can help you fix them.

Not only are there changes within the framework, there are also changes with Discord.js v13.
You will have to update to Node 16 in order to use the libraries due to new JavaScript features.

The suggestions below are not an exhaustive list.
For a full changelog, see here.

Below are renames that will mostly be find-and-replace.

The ClientUtil method fetchMemberFrom has been renamed to fetchMember.

The CommandHandler event commandCooldown has been renamed to cooldown.

The Command option and property channelRestriction has been renamed to just channel.
The Command option and property trigger has been renamed to regex.

The Argument option and property prefix has been renamed to flag.
The Argument method cast has been renamed to process.

Regex types in arguments e.g. type: /^text$/ used to evaluate to an object with the property match and groups.
This has been replaced with an object with the property match and matches.

The match type word has been renamed to phrase.
The match type prefix has been renamed to option.

The TypeResolver property handler has been renamed to commandHandler.

The Listener option and property eventName has been renamed to just event.

Below are breaking changes that may require some more thought when fixing.

The structure of the AkairoClient and the various handlers has been changed.
To see what has changed, start at Setting Up.

Before, in a type function of an arg when returning a Promise, it would only be a cast failure if the Promise rejected.
Now, it will only be cast failure if the Promise resolves with null or undefined.
This is to make async functions easier to use.

Similarly, in inhibitors, a Promise rejection would be used to signify that the message was to be blocked.
Now, with Promises, the Promise has to resolve with true to signify a block.

The following methods are now properties:

• Argument#default
• Command#trigger
• CommandHandler#prefix
• CommandHandler#allowMention

This means that you have to check if its a function before using it e.g.
typeof arg.default === 'function' ? arg.default(message) : arg.default.
This allows for checking if a value was set, such as the default value of an argument.
Of course, if you already know that the property is or is not a function, then there is no need for changes.

The events commandStarted and commandFinished have new parameters.
commandStarted now passes (message, command, args) where args are the parsed args.
commandFinished now passes (message, command, args, returnValue) where returnValue is what the command's exec function returned.

The event commandBlocked is no longer fired when permissions checks are failed.
Instead, a new event missingPermissions is fired.
It will have the params (message, command, type, missing) where type could be either client or user and missing are the missing permissions.

Regex commands used to pass in the values of (message, match, groups, edited).
Now it has been changed to (message, args).
The args object will contain match and matches property similar to a regex type.

CommandHandler options handleEdits will no longer implicitly enable the commandUtil option.
The commandUtilLifetime option also now defaults to 5 minutes.

All the CommandUtil parse information such as command, prefix, alias etc. are moved to the parsed property.

The defaultPrompt option has been changed to argumentDefaults which allow for more defaults.
You can simply move your options into argumentDefaults.prompt.

Argument parsing now uses a new parser.
Some behavior with whitespace and quotes may have changed.

The argument type function used to have a special behavior for when true was returned.
It would use the original user input phrase as the evaluated argument.
Now, it simply is just true.

Argument functions this binding has also been changed.
They will now all point to the Argument instance rather than being inconsistent, where some would point to the command.

The default value of the argument default option is now null rather than an empty string.

Type functions previously would be passed (phrase, message, args).
They now pass (message, phrase).
The previous arguments can be accessed by using a generator for arguments.

Previously, prompt functions would be passed (message, args, retries).
They now pass (message, data) where data is an object.
You can get the retry count, among other properties, with data.retries.
The previous arguments can be accessed by using a generator for arguments.

The argument type invite used to just match an invite from a string.
Now, it will attempt to fetch an Invite object.

All features deprecated in v7.5.x have been removed as well as some unexpected removals.
Suggestions will be made for replacements.

Loading modules by instances is now unsupported.
This means you cannot do, for example, module.exports = new Command(...) or handler.load(new Listener(...)).
Subsequently, this also means that the constructor for AkairoModule and related have also changed.
The constructor is now (id, options) instead of (id, exec, options).
The exec method is now also not on the AkairoModule prototype and should be implemented where needed when extending.

The AkairoHandler method add has been removed.
Use the load with a full path instead.

The AkairoHandler events add and reload have been removed.
The load event will now take care of both.
When reloaded, the load event will pass a second parameter which is a boolean, signifying that is was a reload.

The ability to enable/disable modules have been removed, along with the events.
It is recommended to implement this feature manually instead.

Both ClientUtil prompt methods, prompt and promptIn were removed.
Alternatives includes your own message collector, using awaitMessages, or using Argument#collect.
An example of the collect method would be new Argument(command, argOptions).collect(message).

Selfbot support has been removed.

The command option split is now removed.
Instead, the quoted option is added, which can be true or false, defaulting to true.

The match option on an argument can no longer be a function.

In the command exec function as well as the commandStarted event and some other places, the edited parameter is removed.
To see if the message was edited, you can check with message.edited.

The dynamic and dynamicInt types were removed.
Instead, use a union type e.g. Argument.union('integer', 'string').

Other removals include the send aliases in CommandUtil, deprecated methods in ClientUtil, and some methods in AkairoClient.
Most of them can now be found in Discord.js itself or implemented yourself if needed.