When creating a Lightroom preset, it is saved to a location that all versions of Lightroom share. Therefore, when you install a newer version of Lightroom, presets created in an earlier version are automatically imported.
Note: The setting "Store presets with catalog" in Preferences > Presets causes Lightroom to look for and save your presets to your catalog folder. Enabling this option does not move presets currently in the default folder to the catalog folder. If you have enabled this option in Lightroom and then install a newer version, this preference setting is not passed to the new installation automatically.