According to the Birmingham County FA, long sleeved versions of Coventry City's red/black away kit could be breaching FA Standard of Code Rules.
Whilst City's kit has been approved for use for Football League matches etc, teams who like to wear City's away kit for matches, are advised to check with their league and County FA before purchasing it.
An article on the County FA's website, has the following:"Nike recently launched the new Striped Division II Jersey in spring of this year as part of their new Team Wear 2016 range. This specific long sleeved jersey has been deemed as not meeting the requirements of the FA Standard Code of Rules, being approximately 85% black.
The FA Standard Code of Rules, states in section 9 that “no player, including the goalkeeper, shall be permitted to wear black or very dark shirts.” The new shirts, images which can be seen below, are extremely dull despite the colouring of the stripes, which are not as bright as depicted in these images when viewed first hand."
image: http://www.birminghamfa.com/~/media/CountySites/birfa/images/n/nike-kits.ashx?la=en
More at http://www.birminghamfa.com/news/2016/jul/is-your-nike-kit-compliant#