FAYETTEVILLE, Ark.—Wal-Mart Stores Inc., the behemoth of retail that was founded more than 50 years ago, wants to appear young and tech savvy.

At its annual shareholder meeting, a week-long revival-style event attended by 5,700 store employees, Wal-Mart showed off its use of drones in warehouses, announced a grocery-delivery test with Uber Technologies Inc. and Lyft Inc. and voted in founder Sam Walton’s 34-year-old grandson as a board member.

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