Learn Hardcore Portuguese (Portugal): Eu descarreguei a aplicação ontem, mas hoje ela precisa de atualizar. - I downloaded the app yesterday, but today it needs to update.

descarregar: Eu descarreguei a aplicação.
transferir: Eu transferi a aplicação. (very common on websites and app stores)
fazer o download de: Eu fiz o download da aplicação. (informal/techy calque) Avoid Brazilian baixar in Portugal, where it usually means “to lower (volume/price)” or “to go down.”

Why is it a aplicação and then ela (she) for “it”?

Portuguese uses grammatical gender for nouns, even inanimate ones. aplicação is feminine, so the subject pronoun is ela. If the noun were masculine (e.g., o programa), you’d use ele.

Do I need to say Eu and ela, or can I drop them?

Portuguese is a “null-subject” language, so you can drop them when context is clear:

Descarreguei a aplicação ontem, mas hoje precisa de atualizar. Including eu/ela adds clarity or emphasis. Here, ela helps make it explicit that it’s the app, not “I,” that needs to update.

Why is it precisa de atualizar and not just precisa atualizar?

In European Portuguese, precisar takes de before a noun or an infinitive:

precisar de + coisa/infinitivo: Ela precisa de atualizar.
precisar que + subjuntivo: Ela precisa que eu a atualize. Omitting de (precisa atualizar) is more Brazilian.

Can I say precisa de ser atualizada or precisa de atualização instead?

Yes—these are natural alternatives with slightly different feels:

Ela precisa de ser atualizada. = “It needs to be updated” (passive; someone/system updates it).
Ela precisa de atualização. = “It needs an update” (noun).
Ela precisa de atualizar. often implies “needs to update (itself),” but all three are used.

Why use the simple past descarreguei rather than a present perfect like tenho descarregado?

Portuguese present perfect (tenho descarregado) expresses repeated or ongoing action up to now. A single completed action “yesterday” takes the simple past:

Eu descarreguei a aplicação ontem. (one-time, finished)
Tenho descarregado várias aplicações ultimamente. (repeated)

Is aplicação the usual word in Portugal, or should I say app or aplicativo?

In Portugal:

aplicação (standard) or app (colloquial; often written as a app).
aplicativo is Brazilian. So your sentence with aplicação is perfectly natural in European Portuguese.

Is the comma before mas required?

Yes. Mas (but) is an adversative conjunction and is normally preceded by a comma:

… ontem, mas hoje …

Where can I put ontem and hoje in the sentence?

Common placements:

Ontem descarreguei a aplicação, mas hoje ela precisa de atualizar.
Descarreguei a aplicação ontem, mas hoje ela precisa de atualizar. Keeping hoje near the clause it modifies (the second one) is clearest.

Could I replace a aplicação with a pronoun later on?

Yes. In European Portuguese you’d typically use enclisis in affirmative statements:

Eu descarreguei-a ontem, mas hoje ela precisa de atualizar. With negation or certain triggers, it moves before the verb:
Eu não a descarreguei ontem. Note: This clitic placement is European; Brazilian usage differs.

Does descarregar have other meanings I should be aware of?

Yes. It also means:

“to unload” (a truck): descarregar o camião.
“to discharge/run out” (battery): o telemóvel ficou descarregado. Context (with aplicação) makes “download” unambiguous here.

Is atualizar the correct spelling in Portugal? What about actualizar?

The post-1990 orthography (official in Portugal) writes atualizar. You may still see actualizar in older texts, but atualizar is the current standard.

Could I use para instead of de after precisa?

After precisar, use de. para expresses purpose in a different slot:

Ela precisa de atualizar.
Ela precisa de atualizar para funcionar bem.

Any quick pronunciation tips for tricky words?

Approximate European Portuguese:

descarreguei: “dsh-kah-heh-GAY” (strong H-like sound in rr; final “-guei” like “gay”).
aplicação: “uh-plee-kah-SOWNG” (final nasal ão).
hoje: “OH-zh(uh)”.
mas: “mash”.
ela: “EH-luh”.
precisa: “pruh-SEE-zuh”.
atualizar: “uh-twa-lee-ZAR”.