Release notes

Mai 2024, version 78

After several years in service, the app needed an update, mainly because, over the years, Google has been discontinuing some libraries necessary for the Android app, such as those related to single sign-on and push notifications.

On the other hand, we have decided to make the app completely free for now, and all libraries related to in-app purchases have been removed.

Unfortunately, the app now only works on Android 4.4+ devices. On the plus side, for now, the app is free.

October 2019, version 67

The main novelty of this release is the “Boost Mode”, a new feature requested by the users. With this new feature you can set a target temperature and a period of time, for example, “24º and 45 minutes”. The thermostat will try to reach the specified temperature, and after the established period, it will continue with the previous state to the boost mode.

Another feature requested by the community is the possibility of see the stats recollected by the thermostat and export them to CSV to further analysis. We are in the earlier stages of the development, but you will find a preview of this new feature on the Smart Thermostat website.

When logged in with your username, you will find two new menu options: “My Smart Thermostat” and “Thermostat Stats”. In the first section, you will find information about the current state of your thermostat, and in the second section, you will see some graphics with temperature stats between dates. You have the possibility to export this data to a CSV file and download it.

Besides those new features, as usual this version has some minor bug fixes and performance improvements.

Release March 2019, version 61

The release of this month has a couple of important news:


  • There was a bug in the relay sketch preventing the ESP32 from turning off the boiler when the internet connectivity was lost. This bug is fixed in the new release of the sketches. Although the new Android app will work with the old versions of the sketch, it is recommended to update it.
  • With the new version of the sketch, you can use a LOW LEVEL TRIGGERED relay if you want. There is a flag in the configuration section to set the type of relay used.

Android app

  • A couple of buttons were added to the user interface to make the adjustment of the desired temperature easier.
  • New feature “temperature not increasing” alarm: you can enable this alarm to receive a notification when the thermostat is demanding heat but the temperature is not increasing. The alarm is fully configurable and optionally the boiler may be turned off until the problem is solved.
  • As always, a lot of bug fixes and improvements.

Release 02/2019, version 40.

This is a very big update. Although the app may seem the same, a lot of work was done under the hood and there are a couple of important points to keep in mind.

  • We migrated from the Firebase Realtime Database to a custom backend in our private server. That was the biggest change in this release because it forced to develop a custom backend and to rewrite the thermostat app almost from scratch. But the advantages are worth it and will allow new features for upcoming releases.
  • The “Smart Old Relic App” is deprecated, and was removed from the Play Store. The app will continue to work for those of you that are using it as a smart thermostat. But you will not be able to find it anymore in the play store. And,
  • The “Smart Thermostat Client” app was renamed to the “Smart Thermostat” app.
  • Both apps, the Smart Old Relic app (the app for the thermostat), and the Smart Thermostat client app were merged into one app (the Smart Thermostat App). This was done to make the development process and the maintenance easier for us. When starting the app, you will have to select the role of it (thermostat or client).

Regrettably, the changes are so large that we were not able to develop a smooth transition for you. When receiving the update for the Smart Thermostat Client (now simple the “Smart Thermostat” app), it will reset your local configuration, and you will have to link it again with the thermostat.

But of course, the new client app does not work with the old thermostat app, because of that you will have to install the new version of the app in the thermostat also. We request apologizes, but we didn’t find a better way to update the app.

New sketches are required too. You will find them in the resources section. The old sketches will not work with the new Thermostat App.

As said, the “Smart Old Relic Thermostat ” app will continue to work to those of you that have it installed. Because of that, keep in mind that if you update the client app, you will have to remove the “Old Relic app” and substitute it with the Smart Thermostat app, and update the sketches too. Plan the update accordingly.

Release 2018.4


There is nothing new for the ESP32 sketches. Because of that, they don’t need an update.

Smart Old Relic Thermostat and Smart Thermostat Client app.

  • Following the suggestions of the users, I added a switch to lock the thermostat and avoid to change the desired temperature by error.
  • The settings screens were developed again from scratch. Now all settings should be applied correctly.
  • There was a bug regarding the representation of the temperature in Fahrenheit degrees. It is solved now.
  • A lot of bug fixes, especially for the Smart Thermostat Client. Both apps should be more stable now.
  • The app “Client” has a couple of ads. Yes, I know that nobody likes ads on a website or an app, but the project consumes resources and time, and somehow it has to be monetized. I really appreciate your suggestions in this field if you have some.

Both apps have a lot of bug fixes and the internal structure of the local database has changed. Be aware that after installing the update, you will have to re-discover the remote nodes and reconfigure your desired settings.

About the Smart Pi Thermostat version.

Google has released version 0.7 of the developer preview of the Android Things os. That is good news for those waiting for the Raspberry Pi 3b version. Version 1 of Android Things is nearer now. Maybe at the end of 2018?

Release 2018.3


You should update the sketches for the ESP32 microcontrollers. The following features have been added to the sketches:

  • We added a new sketch to control the relay and the temperature sensor with only one ESP32. This would be the cheapest configuration you can achieve. You need only an Android device to act as a thermostat, an ESP32 with and DHT sensor and a high-level relay.
  • A security feature was added to the relay: if the relay does not receive a command from the Smart Thermostat in a reasonable period of time, the boiler is powered off, until the relay receives again a command from the thermostat (useful in the case the Smart Thermostat app is powered off while heating).
  • A different library is used to read the information from the DHT Sensor. This new library is more reliable than the previous one.

Please, update the sketches of your esp’s as soon as possible.

Smart Old Relic Thermostat

  • New security feature: if the thermostat can no connect with the master node in a reasonable period of time, then the relay/boiler is turned off.
  • When discovering nodes, a view was added with a log registry to diagnose problems discovering the remote nodes.
  • Solved a bug when saving the settings of the thermostat (the new settings were not really saved).
  • For each node, now you will see a yellow warning icon when something with the node is not completely ok. By clicking on that icon, you can see a short description of the problem.
  • In the temperature programs view, now you can increase the temperature in little 0.5º steps.


  • Sketches: there are new versions of the sketches available for the Temperature&Humidity node, and for the Temperature&Humidity&Relay node. A better library to access the DHT sensors is used now.
  • Smart Thermostat Client v 0.2
    • improvements in the user interface (the thermostat spheres were not resizing correctly on some devices).
    • landscape mode enabled
    • bug fixes.
  • Smart Old Relic Thermostat v 0.0.7
    • improvements in the user interface (the thermostat spheres were not resizing correctly on some devices).
    • added an option to generate a QR code in the thermostat, to configure the client apps.
    • bug fixes.

February 2018

Smart Thermostat Client 0.1

  • Many bug fixes.

Smart Old Relic Thermostat 0.0.6

  • Improved the discovery of remote nodes (relays or temperature/humidity sensors). The thermostat can work now with only one ESP32 controlling both the relay and the sensor. A special sketch is needed for that.
  • A problem discovering nodes by Android O fixed.

January 2018

Smart Thermostat Client 0.0.9

  • A lot of bug fixes and a new feature: you can establish programs for each day of the week, with different heat periods for each day.

Smart Old Relic Thermostat 0.0.4

  • Besides a lot of bug fixes, the Thermostat now can work in auto mode, that is, you can establish a program with the client app, and when in auto mode the thermostat will follow that heating program.