You can download the latest versions directly from you Links SQL admin area, if you are a registered user.
When you install and the installer detects an already existing version of the plugin, you click on the overwrite button at the bottom. Both plugins also ask you if you want to overwrite the existing tables, which you should set to 'No' (otherwise your attachment/page database will be lost). The default is set to 'No', so it won't overwrite any tables in your database.
EDIT: I should add that the plugin options will be changed back to the default ones when you upgrade. I advise you to open the page with the current plugin options (for either PageBuilder or Attachment) in a separate browser window, do the upgrade with a different browser window. After the upgrade you can just copy/paste the old options to the version.
Does that answer your question?
Ivan
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Iyengar Yoga Resources /
GT Plugins