A handy addition in XSLT 2.0 is a nice set of date and time format XPath functions. XSLT 1.0 was decidedly lacking in these functions, so you may have used a third-party library such as EXSLT for this purpose. EXSLT offers arithmetic functions on dates and times (still absent in XSLT 2.0) but the XSLT 2.0 offering is perfect for formatting dates and times as strings. It also means that you don't have to worry about importing the third-party library.