pm2 logs are disappearing after 5 days

Question

Even though I specify "numBackups" as "90" I'm only seeing 5 log files, older ones are being removed.

This is how I start the server

pm2 start server.js --name app_server --log log/app.log --time

This is my full log4js.json

{
    "appenders": {
        "server": {
            "type": "file",
            "filename": "log/app.log",
            "pattern": "yyyy-MM-dd",
            "numBackups": "90",
            "compress": true
        }
    },
    "categories": {
        "default": {
            "appenders": [
                "server"
            ],
            "level": "DEBUG"
        }
    }
}

Answer 1

numBackups has been replaced with backups attribute