Apple (NASDAQ:AAPL) did it. The tech giant made it through a week in which Samsung unveiled the Galaxy S4 and BlackBerry (NYSE:BB) announced a record purchase order as plans for the stateside release of its new Z10 firmed up.

And Apple didn't just survive last week. It outright thrived. Shares rose 2.8%, leaving this month's 52-week low of $419 shrinking in the rearview mirror.

It's OK to exhale, Apple investors -- for now. The coast isn't exactly clear. There are plenty of upcoming challenges, and it's never too early to start circling dates before the bears close in again.

March 22
AT&T (NYSE:T), the first wireless carrier on the planet to sell the original iPhone, will also start selling BlackBerry's Z10 on Friday. Verizon (NYSE:VZ) follows six days later, and the country's two largest wireless service providers are already taking preorders for the phone that features the bar-raising BlackBerry 10 mobile operating system.

It's a safe bet that BlackBerry was referring to either AT&T or Verizon Wireless when it revealed a few days ago that it received the first purchase order for a million smartphones in company history.

Apple's iOS seems locked into second place in mobile operating systems. It's not going to catch up to Google's (NASDAQ:GOOGL) Android, and BlackBerry 10, Windows Phone 8, and other overseas flavors lag safely behind. However, Apple still needs to keep on top of every rollout.

April 23
Apple will report its fiscal second-quarter results next month, on or around April 23.

The fallen tech darling's reports used to be a time to celebrate. Apple would blow past its intentionally conservative guidance. Analysts would scramble to push their targets higher. The process would repeat itself three months later.

Life has been far more challenging during the Tim Cook era. Apple has come up short against Wall Street's profit targets in three of the past six quarters, missing the mark in two of the three previous periods.

Investors will gravitate to Apple's margins in the report. The company's once chunky margins have been contracting as consumers choose lower-margin iPad Mini and iPhone 4 and iPhone 4S devices over full-sized iPads and iPhone 5 smartphones. The end result is that analysts now see profitability declining by 17% for the quarter on a modest 9% revenue increase.

If Apple is still a growth stock, it's going to have to prove it next month.

April 26
Samsung's flashy rollout for the Galaxy S4 on Thursday night doesn't mean the hottest brand in Android-fueled smartphones will hit the market right away. Samsung is pointing to April 26 as a release date in the U.K., and similar availability in late April is expected closer to home.

There will be hype for the device that outmuscles the iPhone 5 on several fronts. No one expects Apple's next iPhone to hit the market any earlier than the middle of this year, so the pressure will be on for Apple to beef up its marketing expenditures to extol the virtues of its device as larger and flashier S4 handsets enter the wild.

Apple already went on the offensive on the eve of the Galaxy S4 event. It can't afford to take a breather now that the stock is starting to gain some initial traces of momentum.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.