Smartphones eventually become outdated as most manufacturers don't update them for years, this is why you may end up with outdated software on your old device, how ever there is this portal named XDA where you will find alot of developers who try to get latest available software for your old android smartphone via custom roms.

Custom rom is a third party software developed out of Google's Android open source project which developers use to create software / custom roms for your android powered smartphone based on kernel, processor, hardware features etc as most smartphone manufacturers put an end to official software updates after few years, in that scenario custom roms will be the only choice to experience the latest software on your old smartphone.

But, in-order to install custom roms on your android smartphone you have to unlock bootloader which voids warranty and install custom recovery like TWRP to flash custom roms, how ever you have to properly unlock and install custom roms 
based on guidelines set by your custom rom developer else you can end up with hard or soft bricking your smartphone.

This is why, kindly check XDA portal to get proper bootloader unlocking and recovery flashing guides especially made for your device from developers, including that you can only flash custom roms that are made specifically for your android device, this is little lengthty procedure so alot of people stay away from custom roms stuff.

Usually, on XDA " developers " try to bring latest possible software update to old Andriod smartphones but due to lack of hardware features, kernel, drivers etc required by Google's latest android software, numerous old android smartphones end up unsupported, this is totally understandable and makes sense.

However, on XDA there are some developers who can make impossible possible you heard it right! recently a few talented developers named Althafvly, chill360 and more successfully booted Andriod 12 lineage OS cusom rom on Moto G3 with device code name Osprey and merlin released in July 2015 with Qualcomm Snapdragon MSM8916 which is now 8 year old, this is pretty suprising and amazing to see while some new and powerful smartphones were struggling to boot Andriod 12 like Moto G5 plus.

Even though Moto G3 2015 osprey is pretty old smartphone, but due to geeky developers like Althafvly Chil360 and other contributors, users of Moto G3 Osprey and merlin were able to get hands on latest Android softwares, not just Andriod 12 but also previous android versions as alot of custom roms already available for Moto G3 2015 from many developers to keep it up to date and alive.

Althafvly, chil360, squid2, jeferson1979, Alberto97 has done fabulous job to boot and bring Andriod 12 lineage os custom rom on Moto G3 Osprey / Merlin, I'm pretty sure there is alot of hard work behind this, how ever as this is new build there are few things not working like VoLTE, Encryption, SElinux encryption, and UI is little laggy which can be fixed in future updates.

Right now, on Andriod 12 lineage OS build for Moto G3 Osprey / Merlin, only camera and flashlight, WiFi, battery led, bluetooth, telephony ( calls and data ), Audio ( record and playback ) videos playback, sensors, GPS etc are working and do note custom kernels are not supported, only stock kernel and offical builds are supported.


• Moto G3 Osprey / Merlin custom rom development support •

XDA

Remember, if you own Moto G3 Osprey or Merlin and ready to flash LineageOS 19 then make sure your firmware version is atleast on Marshmallow and Gapps can only be flashed on clean installations, all user data including internal storage will be wiped if stock rom is previously installed & device is encrypted, for updated detailed information on this check XDA thread.

• How to download LineageOS custom rom for Moto G3 2015 Osprey / Merlin •

It is very easy to download LineageOS 19 from these platforms for free.


• How to install LineageOS 19.0 on Moto G3 2015 Osprey / Merlin •

- Reboot to recovery
- Format system, data, cache
- Install LineageOS zip.
- Reboot

Finally, Kudos to Althafvly and other contributors for bringing Andriod 12 for Moto G3 2015 osprey and Merlin, you can donate Althafly on PayPal to support him, do you own Moto G3 2015? have you tried this Android 12 LineageOS 19 built? If yes do say you experience and what how do you feel about Andriod 12 on Moto G3 in our comment section below, see ya :)