Digital Monster ver.4 (デジタルモンスターＶｅｒ．4 Dejitaru Monsutaa Ver. 4) is the fourth series of the Digital Monster virtual pet.

Evolutions

Baby I

Monochromon:
- Piyomon: 0-3 Calls, Train 48+.
Cockatrimon:
- Piyomon: 4+ Calls, Train 5-31, Overfeed 3+, 0-4 Sleep Disturbances.
Leomon:
- Piyomon: 0-3 Calls, Train 0-47.
- Palmon: 0-3 Calls, Train 48+.
Kuwagamon:
- Piyomon: 4+ Calls, Train 32+, Overfeed 3+, 0-6 Sleep Disturbances.
- Palmon: 4+ Calls, Train 8-15, Overfeed 0-5, 5+ Sleep Disturbances.
Coelamon:
- Palmon: 0-3 Calls, Train 0-47.
Mojyamon:
- Palmon: 4+ Calls, Train 16+, Overfeed 6+, 0-4 Sleep Disturbances.
Nanimon:
- Piyomon/Palmon: When you do not fulfill the requirements of other Digimon.

Megadramon:
- Monochromon/Leomon/Coelamon: Fight 15+ battles with a victory ratio 80% or more. (unconfirmed)
Piccolomon:
- Cockatrimon/Kuwagamon/Mojyamon: Fight 15+ battles with a victory ratio 80% or more. (unconfirmed)
Digitamamon:
- Nanimon: Fight 15+ battles with a victory ratio 80% or more. (unconfirmed)

General
- The counters are reset when the Digimon evolves. So, for example, nothing that happens to the newly hatched Digimon affects growth at all.
- The requirements for Perfect Digimon are unknown at this time. Some battles are necessary.
Calls/Care Mistakes
- When its hunger hearts run out, the call icon lights up. If you don't feed it for 20 minutes, it goes out again, and that's a care mistake. The same for strength. However, if BOTH hunger and strength run out, it's still only one care mistake. And if you leave it for a few hours before feeding it, and it bleeps again a few times, then even then it's only one care mistake.
- Lights calls are straightforward - leaving the lights on for 20 minutes after it falls asleep is a care mistake.
- Accumulating up to 4 piles of poop has no effect at all. (Larger quantities are unknown.)
Training
- Only successful training is counted for evolution.
Overfeeding
- To overfeed, stuff the Digimon with food until it won't eat any more. It is necessary to wait until it loses a hunger heart before overfeeding it again.
Sleep Disturbances
- Wake the Digimon up by going into the Food menu, training it, or selecting the Battle option.
- If you want to wake it, without this being counted as a wakeup, then set the clock to some time during the day. The Digimon will wake up, with no effect on the counters.