We report on recently conducted technical developments of front- and back-end for four 20-m radio telescopes of VLBI Exploration of Radio Astrometry (VERA). In this short article, a brief overview of the developments of a dual circular polarization receivers and ultra-wide band (16 \gbps) recording systems that were installed to each of the four telescopes of VERA is presented.
With the new technical developments that enable wider band VLBI polarization observations at 22 and 43 GHz bands, it is expected that VERA will reveal magnetic fields in plasma jets of active galactic nuclei, masers in star-forming cites, and late-type stars at unprecedented sensitivity.
The wide band calibrated spectra, delay solutions, and the polarization intensity maps of extragalactic sources at 22 and 43 GHz that obtained from the most recent test observations are presented to show the current capabilities of the VERA polarimetry performance.