Chicagoboss - How to update lager_file_backend config?

I have updated ChicagoBoss to my latest version. When I'm compiling it, I'm getting a notice as

Deprecated lager_file_backend config detected, please consider updating it

I'm compiling it using following command:

 ./rebar get-deps clean compile

So, the questions are:

• What is lager_file_backend config?
• Why it is deprecated?
• How to update it.?

• lager_file_backend config simply refers to the 'lager_file_backend' section of your configuration file (boss.config)

• I don't know why it is being deprecated, sorry.

• I had trouble finding release notes detailing the differences. I figured out how to update by looking at the example here: https://github.com/basho/lager

Here's what the old style looks like:

{lager, [
    {handlers, [
      {lager_console_backend, info},
      {lager_file_backend, [
        {"/var/log/foo/boss_error.log", error, 10485760, "$D0", 5},
       {"/var/log/foo/boss_console.log", info, 10485760, "$D0", 5}
      ]}
    ]}
  ]},

Here's what the new style looks like:

{lager, [
    {handlers, [
      {lager_console_backend, info},
      {lager_file_backend, [{file, "/var/log/foo/boss_error.log"},  {level, error}]},
      {lager_file_backend, [{file, "/var/log/foo/boss_console.log"}, {level, info}]}
    ]}
]},