The EEOC recently issued its interpretation of Title VII's requirements that employers accommodate religious practices of their employees. The guidance is here. The only thing that I would note in this publication, which is merely a restatement of current law, is that the EEOC is using the words "undue hardship" into this guidance. However, the term "undue hardship" does not mean the same thing as the phrase does in the context of other employment statutes requiring accommodation, such as the Americans with Disabilities Act.
In fact, the law regarding religious accommodation has remained relatively stable for several decades-an employer is not required to accommodate a religious practice of an employee if doing so would create more than a "de minimis" effect in the workplace. This is a significantly lower standard of harm that an employer has to demonstrate than is found in the ADA. I'm not sure why the EEOC is using the same term, except perhaps in an attempt to get people to believe that the burden is somehow higher than it actually is.