Absolutely. While newer microcontrollers (ESP32, RP2040) have more power, the K3NG schematic remains the standard because:
The K3NG Keyer is not just a simple oscillator; it is a full-featured communication hub. Its versatility comes from a modular code design that allows builders to enable only the features they need. k3ng keyer schematic
Let’s say you want to key a vintage Heathkit transmitter that uses grid blocking keying. You cannot use a standard NPN 2N2222. Here’s the modification: Absolutely