Learn Hardcore Indonesian: Besok kuliah dimajukan, jangan sampai salah jadwal. - Tomorrow the lecture is moved earlier; don’t get the schedule wrong.

It means the class is moved earlier (brought forward). The common opposite is diundur/diundurkan (moved later, postponed). Memory tip: maju = forward → earlier; mundur/undur = backward → later.

How is dimajukan formed, and what voice is it?

It’s passive: di- + maju + -kan → dimajukan “to be moved forward.”
Active voice: memajukan (someone moves something earlier).

Active: Panitia memajukan kuliah besok.
Passive: Kuliah besok dimajukan (oleh panitia).

What does kuliah mean here—class, course, or to study?

Here kuliah is a class/lecture session. It can also be a verb meaning “to study/attend university,” as in Saya kuliah di UI “I study at UI.” For “course,” use mata kuliah.

Can I change the word order, e.g., Kuliah besok dimajukan?

Yes. Time words are often fronted, but both are natural:

Besok kuliah dimajukan.
Kuliah besok dimajukan. Fronting besok just highlights “as for tomorrow.”

Do I need a preposition before besok (like di/pada)?

No. Just use besok. In very formal writing you might see esok hari or pada esok hari, but in everyday use, besok stands alone.

Who is doing the moving in kuliah dimajukan?

It’s unspecified (passive). You can name the agent with oleh if needed (e.g., oleh dosen/sekretariat), or switch to active: Dosen memajukan kuliah.

What does jangan sampai add compared to plain jangan?

Jangan is a direct prohibition (“don’t”). Jangan sampai adds a caution/“don’t let it happen” nuance—softer, warning-like: “make sure this doesn’t happen; don’t end up …”

Is salah jadwal grammatical even without a verb?

Yes. Indonesian allows adjectival/stative predicates. Salah functions like “to be wrong,” and jadwal is its complement: “be wrong about the schedule.”

What exactly does salah jadwal mean? Is it a schedule clash?

It means you get/follow the wrong schedule (wrong day/time). For a clash/overlap, use bentrok jadwal or jadwalnya bentrok.

How can I state the new time/day explicitly?

Use ke or (men)jadi:

Besok kuliah dimajukan ke jam 8.
Kuliah dimajukan menjadi hari Rabu.
Presentasi kamu dimajukan ke sesi pagi.

What’s the opposite way to say it was moved later?

Use diundur/diundurkan:

Kuliah besok diundur ke jam 3.
Rapat diundurkan ke hari Jumat.

How do I spell di- here—together or separated?

Together, because it’s a prefix: dimajukan. The preposition di (location) is separate: di rumah, di kampus.

Can I add -nya to make things definite, like “the class”?

Yes: Kuliahnya dimajukan = “The class has been moved earlier.”
For the schedule: Jangan sampai salah lihat jadwalnya (“don’t get the schedule wrong”). Using -nya marks something known/specific.

Is this sentence formal or informal? How would a formal notice look?

Neutral–informal, good for chats/messages. A more formal notice might say: Perkuliahan besok dimajukan. Mohon mencermati jadwal.

What’s the difference between kuliah and kelas here?

Kuliah: a university lecture/session; also the act of attending university.
Kelas: a class group or classroom; used more broadly at school levels.
At university, kuliah is the safest choice for a lecture session.

Are there other natural ways to say “Don’t get the schedule wrong”?

Yes:

Jangan salah lihat jadwal.
Jangan sampai keliru jadwal.
Jangan tertukar jadwal. If the concern is missing it: Jangan sampai ketinggalan/terlambat.

Does dimajukan only refer to time, or also to order/priority?

Both. It can mean earlier in time or moved up in sequence/priority:
Agenda Anda dimajukan ke urutan pertama.

Is memajukan the same as mengajukan?

No. Memajukan = to bring forward/advance/promote. Mengajukan = to submit/put forward (a proposal/request): mengajukan permohonan.