The global expansion of industry and technology has brought various environmental issues especially in atmospheric pollution and global warming. These resulted in various R&D activities on renewable energy resources and devices. Developing high temperature polymer electrolyte membrane fuel cell (HT-PEMFC) is one of them. Over the past decades, this research has been received the most attention for various stationary and transportation applications. This is due to inherent advantages of operation above 100 °C including improved tolerance toward CO poisoning, enhanced electrode kinetics, easier heat dissipation and water management as well as better thermodynamic quality of the produced heat. Poly (benzimidazoles)-phosphoric acid (PBI/PA) is the well-established membrane for HT-PEMFC applications replacing perfluorinated sulfonic acid (PFSA) membranes, which operate in the temperature range of below 100 °C. Nevertheless, there have been concerns on the durability and stability of such PEMFC, which negatively affected their widespread commercialization. In this paper, problems regarding this acid-base complex membrane system and modifications as well as some techniques used to overcome these issues will be outlined. © The Authors, published by EDP Sciences, 2019.