I made a new commit o GitHub this morning. For avr (Atmega) architecture the excryption module is using PROGMEM to get another 256 butes of memory. of course for other architectures (ESP8266 and Teensy) the normal definitions are used.
At my last compile of the mini sensor with I2C temperature/humidity sensor I was left with 439 bytes of memory.
Hope it will enable our favourite sketches to run on the Atmega 328 along with the LMIC stack..Let me know if it does.
Maarten