Scrubbs, there's a readme file that lists all of the upgrades done to each version

It can be found in the Virtual Families folder. (Windows)
Here's the list for Mac Users (note, the information is the same for both PC & Mac)
Fixed in 1.00.05
- Life event notifications were sometimes mixing up people's names when it coincided with someone going off to college. Fixed.
Fixed in 1.00.04
- People will sleep to a higher level of energy replenishment
- Adjustments made to offline food consumption, in-game hunger and eating
- Adjustments made to allow greater player influence on longevity
- Failsafe put in for refusal to breed
- Adjustments made to a couple of the more difficult trophies
Fixes in 1.00.03
- Working is a bit less tiring, other changes to energy usage and recovery
- Fix to prevent glove loss/corruption
- Emails-to-player now correctly reflect customized names
- New pet behaviors
- Pets no longer show up in store rotation once purchased
- Store rotation now every 4 hours instead of 8
- Story book shop item works now
Fixes in 1.00.02
- Unleashed several dozen missing behaviors. Get ready to see your family doing some new stuff.
- Tutorial no longer blocks checking of email for office career peeps
- Fixed some breeding bugs
Fixes in 1.00.01
- 2nd generation people no longer occasionally brainless
- 2nd generation people no longer occasionally inheriting 0 energy and 0 happiness
- Invisible pinball machine removed