2017-06-01 20:54:36.4636|ERROR|CitizenMP.Server|Error executing event handler for event es:getPlayerFromId in resource essentialmode: Exception has been thrown by the target of an invocation.
2017-06-01 20:54:36.4639|ERROR|CitizenMP.Server| at [U] System.Reflection.MonoMethod.Invoke(Object obj,BindingFlags invokeAttr,Binder binder,Object[] parameters,CultureInfo culture)
2017-06-01 20:54:36.4639|ERROR|CitizenMP.Server| at [U] System.Reflection.MethodBase.Invoke(Object obj,Object[] parameters)
2017-06-01 20:54:36.4639|ERROR|CitizenMP.Server| at [U] System.Delegate.DynamicInvokeImpl(Object[] args)
2017-06-01 20:54:36.4639|ERROR|CitizenMP.Server| at [U] System.MulticastDelegate.DynamicInvokeImpl(Object[] args)
2017-06-01 20:54:36.4639|ERROR|CitizenMP.Server| at [U] System.Delegate.DynamicInvoke(Object[] args)
2017-06-01 20:54:36.4639|ERROR|CitizenMP.Server| at [U] CitizenMP.Server.Resources.ScriptEnvironment.TriggerEvent(String eventName,String argsSerialized,Int32 source)
2017-06-01 20:54:36.4639|ERROR|CitizenMP.Server|Inner exception: Exception has been thrown by the target of an invocation.
2017-06-01 20:54:36.4649|ERROR|CitizenMP.Server|Inner exception: Exception has been thrown by the target of an invocation.
2017-06-01 20:54:36.4649|ERROR|CitizenMP.Server|Inner exception: Object is nil.
Just do a quick google, someone has uploaded the old version on a GitHub.
To be fair, if he wants people to move to the newer version, he should provide the tools to easy convert from mysql to couchdb so plugins can easily update/switch to support the newer version. But as it stands now, plugin creators can’t really be arsed to switch as it’s a hassle to do so.