Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of a feed additive containing endo‐1,4‐β‐xylanase produced by Trichoderma citrinoviride DSM 34663 (Hostazym® X). The product is authorised as a zootechnical additive (digestibility enhancers) for use in all poultry species for fattening, for laying and reared for laying, weaned piglets, pigs for fattening and carp. The current opinion concerns the request for the renewal of the authorisation for the use in those species/categories and the extension of use to all poultry species for breeding and reared for breeding, ornamental birds, suckling piglets and minor porcine species for fattening. The applicant provided evidence that the additive in the market complies with the conditions of the authorisation. There is no new evidence that would lead the Panel to reconsider previous conclusions that the additive is safe for the target species, the consumers and the environment under the authorised conditions of use. This conclusion also applies to the target species for which a request for extension of use is made. The additive is considered not a skin corrosive or skin sensitiser, but it is an eye irritant. The Panel cannot conclude on the potential of the additive to be a skin irritant. Due to the proteinaceous nature of the active substance, the additive is considered a respiratory sensitiser. The Panel considers that the additive has the potential to be efficacious in all poultry species, ornamental birds, all growing Suidae and carp at the proposed conditions of use.