Operating continuously at a high temperature is possible if you use a stainless steel housing, however it is not recommended. The membrane may oxidize and the contactor service life is reduced. There is a larger quantity of water vapor formed which crosses the membrane to the gas side. The vapor will condense as liquid water on the gas side or in the vacuum line and potentially block the flow path to vacuum pump.  You may also need to consider a higher N2 rates and a larger vacuum pump for DO applications at higher temperatures.