Quantum Espresso 6.3 release notes
New in 6.3 version:

New implementation, using a more robust algorithm for the WignerSize construction in EPW. (Samuel Ponce and Carla Verdi)

New application for optical spectra computation using optimized basis sets (Paolo Umari, Nicola Marzari and Giovanni Prandini).

Improved interface between TDDFPT and Environ using plugins( Oliviero Andreussi)

Improved FFT threading (Ye Luo, Argonne)

EXX: ACE can be projected on arbitrary number of orbitals Slight change in SCF convergence with ACE (dexx) properly accounting for difference between 2*<newV(old)new> and <newV(old)new> + <oldV(new)old> (see "fock3" term) SCDM and localized exchange is now compatible with ecutfock Localized exchange can deal with virtual orbitals (empty bands) (Ivan Carnimeo)

Spinpolarized X3LYP (experimental)

EPW: Electronic transport (Boltzmann transport equation) Iterative Boltzmann transport equation (experimental) Improved way to compute WignerSeitz vectors Cumulant treatement (model) Possible screening Support for exclude bands Calculation of velocity beyond the local approximation (experimental)
Problems fixed in 6.3 version:

Stress with hybrid functionals and Gamma point was grossly wrong (5ed14864)

EPW: Velocity in the dipole approximation was unstable because of Gvector ordering.

Realspace augmentation functions were crashing with nt N option

Calculation of ELF wasn't always working due to a bad usage of FFT descriptors  noticed by Enrique Zanardi Maffiotte (commit a86fb75d)

Workaround for gfortran bug in FoX (commit 5b36b697) and for pgi+openmp bug (f43e72c9)

Reading of starting wavefunctions from file, including restart case, wasn't always working as expected. This might be at the origin of mysterious "davcio errors" (April 18, 2018)

Parameters for electric fields were not saved to the new XML file, thus breaking some forms of postprocessing (noticed by Thomas Brumme and Giovanni Cantele, fixed April 18, 2018)

Bug in reading (with FoX) the augmentation part of pseudopotentials in upf v.2 format. The bug shows up only for PPs generated using David Vanderbilt's code, yielding a mysterious message "Error in scalartorealdp Too few elements found" (March 20, 2018)

LDA+U for spinorbit (kind=1) was crashing for one kpoint, trying to read data not previously saved (noticed by Christof Wolf, Feb 8, 2018)

ibrav =13 wasn't documented and did not recognize the correct parameter cosBC (noticed by Jose' Conesa, Jan 26, 2018)

Yet another problem with the final scf step in a vcrelax calculation: if restarted from an interrupted calculation, the final step was trying to read the charge density with a different number of Gvectors (Jan 23, 2018)

CP with LDA+U: the choice of the LDA+U manifolds from atomic wavefunctions was sometimes not working properly due to a missing check (Jan 22, 2018)

pw2bgw.x fixed, courtesy G. Samsonidze (Jan.16, 2018)

Band parallelization was broken in one of the last commits just before v.6.2.1 (Dec.23, 2017)

TDDFPT in "lr_addus_dvpsi.f90" had a bug for systems with USPP and more than 2 atoms (Dec.22, 2017) (Oleksandr Motornyi, Michele Raynaud, Iurii Timrov, Nathalie Vast, Andrea Dal Corso)

Phonons with images wasn't working in v.6.2.1 with old PP files containing "&" in the header section (Dec.20, 2017)

PWscf in "manypw" mode wasn't working due to a bad IF (Dec.12, 2017)
Incompatible changes in 6.3 version:

EPW: Removal of qpoint paralelization (not very used and generated large code duplication) ==> removal of the parallel_k and parallel_q input variables.

various subroutines computing gradients and similar quantities using FFTs have been harmonized and collected into Modules/gradutils.f90

subroutine "ggen" split into two subroutines: "ggen" takes care of Gvectors for the FFT grid only, "ggens" for the subgrid only

FFT interfaces fwfft, invfft now accept only 'Rho', 'Wave', 'tgWave'. Together with FFT descriptor, these options cover all cases.

Structure for 'custom' FFT (exx_fft) deleted from exact exchange code, FFT descriptor dfftt and a few variables used instead (a different exx_fft structure is still present in GWW)

FFT indices nl, nlm, nls, nlsm, moved from their previous location (gvect, gvecs) into FFT descriptors (dfft* structures)

Development moved to GitLab