@ -13,8 +13,7 @@ In almost all cases, the requirements can be accomplished by changing the firmwa
For updating the firmware on a system being deployed, the system must provide an interface for altering the firmware.
In addition, such an interface should provide mechanisms to check which firmware is currently installed and which configuration parameters are used.
Even if systems are equipped with an interface for applying updates, the maintenance cost can still be enormous if an administrator has to interact with each device physically.
For systems that are located in areas where reachability is limited the cost increases even more.
Even if systems are equipped with an interface for applying updates, the maintenance cost can still be enormous if an administrator has to interact with each device physically if the systems are located in areas where reachability is limited.
If a system is already able to communicate over a network interface, this can be leveraged to apply updates on these system - this is typically referred to as \textit{Over the Air (OTA)}.
By reusing the existing communication channels, the dedicated update interface can be omitted which leads to smaller packaging and reduces production cost.
It also decreases the maintenance cost drastically, because updates can be triggered remotely.
Wireless sensor and actor networks are a crucial elements of today's effort to support and implement \textit{Industry 4.0} architectures and modern manufacturing processes.
Small programmable logic controllers (PLC) and cloud computing are enabler but also drivers of these new manufacturing paradigms \cite{Nigappa:2016eb}.
Thus, the networked interconnection of everyday objects, the automation of home appliances and environmental metering and monitoring based on sensor and actor networks controlled by ESP-based chipsets are subject of current research.
In \cite{DiNisio:2015fg} a low-cost multipurpose wireless sensor network using \textit{ESP8266} PLCs is introduced.
The usage of \textit{ESP8266} PLCs in combination with Raspberry PI acting as base station for the sensors is discussed in \cite{Thaker:2016fi}.
The usage of \textit{ESP8266} PLCs for sensor networks is discussed in \cite{Thaker:2016fi}.
The article \cite{Kodali:2016hc} presents a home automation solution based on a \textit{MQTT} message queue with \textit{ESP8266}-based sensors and actors.
The control of smart bulbs with PLCs is summarized in \cite{Walia:2016bj}.
Unfortunately, software update mechanisms are not addressed in these publications.
