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After the Long Shutdown 2 the LHC will provide lead-lead collisions atinteraction rates as high as 50kz. In order to cope with such conditions theALICE Time Projection Chamber (TPC) needs to be upgraded. After the upgrade theTPC will run in a continuous mode, without any degradation of the momentum anddE/dx resolution compared to the performance of the present TPC. Since readoutby multi-wire proportional chambers is no longer feasible with theserequirements, new technologies have to be employed. In the new readout chambersthe electron amplification is provided by a stack of four Gas ElectronMultiplier (GEM) foils. Their high voltage settings and orientation have beenoptimised to provide an energy resolution better then 12% at the photopeak of55Fe. At the same settings the Ion BackFlow into the drift volume is less than1% of the effective number of ions produced during gas amplification and theprimary ionisations. This is necessary to prevent the accumulation of spacecharge, which eventually will distort the field in the drift volume. To ensurestable operation at the high loads during LHC run 3 the chambers have to berobust against discharges, too. With the selected configuration in a quadrupleGEM stack the discharge probability is kept at the level of $10^{-12}$discharges per incoming hadron. An overview of the ALICE TPC upgrade activitieswill be given in these proceedings and the optimised settings foreseen for theGEM stacks of the future readout chambers are introduced. Furthermore theoutcome of two beam time campaigns at SPS and PS (at CERN) in the end of 2014is shown. At this campaigns the stability against discharges and the dE/dxperformance of a full size readout chamber prototype was tested. In addition itis reported on charging-up studies of 4GEM stacks and on tests ofelectromagnetic sagging of large GEM foils.

Status of the R&D activities for the upgrade of the ALICE TPC