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UPGRADING.md

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+# Upgrading Guide
+
+See the [CHANGELOG.md](./CHANGELOG.md) for detailed information about what has changed between versions.
+
+This guide is useful to figure out what you need to do between breaking changes.
+
+As always, [submit issues](https://github.com/FortAwesome/Font-Awesome/issues/new) that you run into with this guide or with these upgrades to us.
+
+## 5.0.x to 5.0.6
+
+### SVG Attribute was changed from data-fa-processed to data-fa-i2svg
+
+As part of a bug fix for the release of 5.0.6 we renamed an attribute that was found on `<svg>` elements from
+`data-fa-processed` to `data-fa-i2svg`. We feel this more accurately reflects the intent and purpose.
+
+This attribute is added to any icon that has been generated using `fontawesome.dom.i2svg()`.
+
+Be aware that `data-fa-i2svg` (or `data-fa-processed`) will no longer be present on icons that are created using
+`fontawesome.icon()`.
+
+If you've written and DOM queries that rely on `data-fa-processed` you should get things working again by doing a
+simple find and replace.