What version of the Old Testament did Jesus and the apostles have?

Well...

likely they did not own anything like a complete copy.

Aramaic translations of Torah have been found in synagogues in the region, and so it may be that they had access to Aramaic translations.

The "lingua franca" of the region was Koine Greek, so possibly they had access to the Septuagint.

In the Bible itself, we see several quotes from the Old Testament

- most quotes most closely resemble the Greek Septuagint

- but several more closely resemble the Masoretic (Hebrew) text

and to further complicate the matter, it turns out that several Hebrew texts found among the Dead Sea Scrolls have passages (including some of those quoted in the New Testament) that more closely match the Septuagint than they do the Masoretic Text.

SO:

A - We don't know for sure

B - But Hebrew, Greek and Aramaic versions were available in that region during that period

C - And my unprofessional opinion is that Aramaic is most likely for the less educated among them (given that was probably their native language) and that Greek was the most likely for the more educated among them (for example, Paul, who seems to have been fluent in Greek, and possibly also John and others).

As children they MEMORIZED the whole thing in schools, or with parents.

Muslims TODAY!!...MEMORIZE the Qur'an!!

They did it perfectly

Jesus didn't need it. He wrote it through Scribes and Prophets !! And neither did the Apostles, Since Jesus was The New Covenant !!

The Hebrew Old Testament.

They had the Hebrew scripture which we call the Old testament which was in Hebrew and they also had what is called the "Greek Septugaint", which is the Hebrew OT translated into Greek.

They were familiar with the Septuagint, the same books we have today in the OT.

The Septuagint.