In the media scrum around the papal election, a lot of commentators called for the Catholic church to "modernize" to "stay relevant". As a Protestant I agree my Catholic brothers and sisters could make changes for the better, but "modernizing to stay relevant" has often been a siren song that has, and still does, lead many Christian groups to heresy, torpor, and --- ironically --- irrelevance.
The problem is that calls for "relevance" tend to promote the erosion or rejection of tenets of the historic Christian faith --- such as belief in miracles, divine judgement, the authority of scripture, or even the existence of God himself --- in an effort to make Christianity more palatable to modern people. Many Protestant denominations have wholly or partly gone down this path, including New Zealand Presbyterianism of which I am a member. The effects have been disastrous along many axes. Many congregations have ceased to be Christian in all but name, and are incapable of carrying out God's work in the world. By refusing to officially apostasize, they create vast confusion over what Christianity means and (further) undermine the unity that Jesus' followers should have. And instead of making Christianity more appealing, this drive for "relevance" ultimately kills the congregations that follow it. It's easy to see empirically: unbelieving congregations tend to age and dwindle, and healthy and growing congregations tend to be more orthodox. These trends make perfect sense: if a congregation loses its "saltiness" and becomes a secular club with Christian trappings, why would the average person prefer it over another secular club without the tomfoolery? Not to mention that there can be no evangelism, no spiritual regeneration, and no working of God beyond common grace.
The institutional hegemony of the Roman Catholic church has a lot of downsides, but it has enabled them to mostly avoid going down this path --- for which I am grateful. I pray that they'll continue to ignore misguided calls to change course.
For the church to stay relevant, we must keep teaching the classic gospel of Jesus and keep making disciples in his name. To increase our relevance we need do nothing new, but do the old things better: more Christian unity, more evangelism, more faithful living, more prayer, more love. This won't happen with sweeping pronouncements, election of Popes, or even writing of blogs, but as individual Christians quietly choose to put Jesus ahead of themselves every hour of every day.