Far as saves this is what BlueCat said
Ecchi Sensei Save System:
.) Player A has got a Week 1 save at the end of Day 7
.) Player B only played Week 1 up to the middle of Day 4 and saved there
Players A and B now want to play Chapter 4 (Day 8+9, Day 10+11 (Day 12-14 not available yet)) and load their saves.
After loading, Day 8 starts. But how is that possible? Player B only played to Day 4?
That is because our new super awesome save system analyzes how far you played and from that point onwards, if custom data is missing, the progress is being simulated.
What doesn't work yet is the simulation of certain other data. So far, only decisions are being simulated, not the functions such as the Ecchi Calendar or the Ecchi Charscreen.
That means, if you've never played Ecchi Sensei before and you start immediately with Day 8, there won't be any calendar entries beyond those that are included by default in Day 1.
As of now, the D10+11 Alpha save location is intentionally separated from the previous save directories because some functions in the game are incomplete and you will likely run into issues in the future if you keep using the D10+11 Alpha saves. If you want to load your Week 1 save(s), copy them to the \EcchiSensei-D10+11v0.8\game\saves\ directory. When submitting bug reports, it would be helpful if you can tell us whether you are using a completely new save (started new game in this release), a D8+9 save, or a Week 1 save.
The intention is to finish simulating the other features to make the experience of loading Week 1 saves as seamless as possible and to make the Chapter 4 saves as futureproof as possible. This is why current D8+9 saves and D10+11 Alpha saves are not intended to be used in the future (because they lack the implementation of certain features).
Moderator edit: patreon link removed, thread will be updated soon.