I'm probably missing something, info and dates are not that accurate, sorry - I'd like to have checked more sources - but here we go with some fresh and old news. Since the sport was founded by Baron Pierre de Coubertin and introduced in the 1912 Olympic Games (Stockholm, Sweden) some changes happened to the sport and the most notable are:
1949: introduction of World Championship - sure a great achievement, as result and encouragement of the growth of the sport.
1990: introduction of World Cup Series - like the World Championship, another great achievement for the sport.
1996: introduction of one-day format (?) at least in Olympic Games - to make it more friendly to media coverage, also a discouragement to doping since a performance enhancing substance for shooting has the opposite effect in fencing, for example. It was really a challenge for the pentathletes since all events in one day makes the competition tougher and exhausting. I didn't research enough about the order of the disciplines and honestly can't say how many days it used to last, but in 1992 Olympics (Barcelona, Spain) it lasted 4 days and the order was:
day 2- swimming and shooting;
day 3 - running;
day 4- equestrian.
It was different from what we were used to see in last years (shooting - fencing - swimming - equestrian - running) before the introduction of the combined event in 2009. This change of the order, comparing the 1992 event with the 2008 Olympic event (Beijing, China) - this lazy blogger didn't bother searching when it happened- brought more appeal to the sport, with the handicap start and the definition not only by points, but also in the finish line. A bit frustrating for someone who is cheering on a pentathlete wich best skill is not the running, haha. By the way, do they have photo finish for the pentathlon events? I guess yes, they have, but I can't confirm.
Not only the order has changed, they had to change the length of swimming and running, that used to be 300m and 4km to 200m and 3km. I also found info that riding used to be up to 1100 points (with bigger course), shooting also had changes, since in Montreal Olympics there was a score of 198 and now the Olympic record is 191 of David Svoboda (CZE) in Beijing 2008, so changes in the points system also happened in modern pentathlon history.
2000: it's hard to pick a catch phrase from the feminist movement since there are so many, so I'll go with a contemporary one which is not my favourites: girl power! Women's competition was introduced in Olympic Games at 2000 Olympics (Sydney, Australia). I couldn't find since when there are official competitions for women - not only because I'm lazy this time, but mostly because it's hard to find this info and/or I was unlucky in my search - so let's have 2000 as the year women's competition was introduced (when actually it was first time in Olympic Games). I can say in my defense the database of UIPM go back only until 1999. Anyway, not that surprising it lasted so much since it's a sport very linked to militarism, but instead of criticizing it, I prefer to celebrate this late conquer. A necessary change to the sport, no doubt.
Laura Asadauskaitė (LTU). Picture from parsportu.lv
2009: introduction of the combined event - a sport that don't have enough recognition - in my [s]biased[/s] personal view - keep changing to attract more viewers, and the combined event (shooting + running) was introduced with this purpose. Shooting used to be the first event, indoors, while running was the last event. It's a big change! The athletes are tired, the shooting is outdoors... it's interesting two of the top pentathletes this year, Ádám Marosi (HUN) and David Svoboda (CZE), wear glasses. Of course athletes were reluctant about this change, especially when it seemed to reduce their chances, but it seems there is a consensus this change again helped the sport in making it more interesting for viewers, and also it seems the performance/results were not that affected by the new format.
2010/2011: laser pistol replacing air pistol - the last UIPM Congress (Kopenhagen, Denmark) approved this change, to be tested in 2010 and then probably introduced in 2011. The reasons are environmental (less damage to the environment) and to suit better the new format after the combined event (outdoor range shooting). As I've never fired a gun, I can't really say much about this, I hope athletes can adapt well to the new guns and that it won't affect too much the shooting specialists. That's it. Please correct me if necessary.