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To correct the data already processed possible solution is to introduce energy correction to reconstructed energies linear with time.
The evolution of calibration coefficients for each individual crystal since launch was fitted by linear function, the slopes obtained from these fits for all crystals are shown on the following histogram: 
As one can see, the spread of these slopes are very substantial and much bigger than the staistical error (~0.2%).
The time eveolution of the calibration coefficient for typical channel (tower=0, layer=0, col=0) and two channels from the "left tail" of the histogram (tower=11, layer=1, col=11 and tower=15, layer=0, col=4) are show below:
It is evident that for the crystals with big change in calibration the evolution is not linear with time.
The fact that the calibration coefficients evolve differently for different crystals and in general not linearly with time requires that we use up-to-date set of calibration coefficients for pipeline processing.