To sum up latest discussions etc from Slack, the latest proposal would be as follows:
offset = description 0 = Data format (8bit) whatever the next number will be (likely 5) 1-2 = Temperature (16bit signed) in 0.005 degrees (-163.84 to 163.83 range) 3-4 = Humidity (16bit unsigned) in 0.0025% (0-163.83% range, though realistically 0-100%) 5-6 = Pressure (16bit unsigned) as it is in format 3 7-8 = Acceleration-X (16bit signed) as it is in format 3 9-10 = Acceleration-Y (16bit signed) as it is in format 3 11-12 = Acceleration-Z (16bit signed) as it is in format 3 13-14 = Power info (11+5bit unsigned), first 11bits unsigned is the battery voltage above 1.6V, in millivolts (1.6V to 3.647V range). last 5 bits unsigned is the TX power above -40dBm, in 2dBm steps. (-40dBm to +20dBm range) 15 = Movement counter (8bit unsigned), incremented by motion detection interrupts from LIS2DH12 16-17 = Measurement sequence number (16bit unsigned), each time a measurement is taken, this is incremented by one, used for measurement de-duplication (depending on the transmit interval, multiple packets with the same measurements can be sent, and there may be measurements that never were sent) 18-23 = Tag ID, the 48bit MAC address (rather than the hw ID on the nRF chip to provide compatibility with current datasets that differentiate tags based on the MAC)
Most notable was replacing packet sequence number with measurement sequence number, as it’s more relevant for measurement de-duplication.