Tasha didn't have ANY Serum Routes. Now she does
Ava didn't have Serum Endings. Now she does
You can't expect your save to work on old coding that just doesn't exist anymore. The new content for Tasha completely changed how she works. That is why Saves were broken.
But on another note, Free Play exists. You can basically catch up to where you were within an hour. That's another reason why it exists
True but with Tasha before you had an option.
Now serum or no serum, if you're nice to Tasha, you end up dating her. I tried not dosing her at all, and then I get talked to in the early morning by Tasha about our date (what date I haven't even talked to her), and I can not dose her after this because I'm "dating" her.
Tried to dose her, to get the morning scenes in her office and in the lab, but those were changed so you can only talk to her in each location.
In one instance we were supposed to be dating (still wasn't sure how that happened), go to head office, yet Tasha ignored me the whole time there and Sophie came to my room for sex at night.
Tried to dose her, she came to the lab in the morning, kissing scene (great right path to use her.......NOPE), next dose is convince her she's in love with you.
So no matter what any interaction with Tasha now leads to dating her, willingly or not.
John Dom route completely nerfed now.
Tried not dosing anyone except Sophie, Dianna, and Kagney following the usual route for Dom path and got to where I couldn't say no to John. 3 chapters later still the same with no progression.
Tried typical playthough, dosing Penny to embracing her sexuality (but not dom), done the getting force dosed by John after multiple times submitting to John, same result.
Tried getting him angry and coming at me, both getting knocked down and submitting and knocking him down, eventually getting to where I could submissively try and dose him, gets same result.
Every path so far out of 13 attempts have led to you blowing John and Penny commenting about it the rest of the game.
So the only real choice here now is just follow the Chanele route.
Also since the last update the Wiki is severly outdated now and cannot be followed