Sony has released an optional firmware update for PS3. If you have automatic updates enabled, you'll see the update ready to install on your system. Otherwise, you'll need to manually update your console.
According to the update notes, 4.53 adds one new feature: support of closed captions while playing Blu-ray movies. Every other feature, including support for automatic downloads, was introduced in 4.50.
While most Blu-ray discs support subtitles, support for closed captioning has been difficult due to complications regarding HDMI specifications. So, seven years after PS3's launch, it can finally support the feature.