This might be a reference to this one: https://github.com/facebook/react/issues/10212#issuecomment-346302374

The problem still exist.

So, trying to render with server side and got this error. I don't have this notation in my code but this might be a problem with dependencies.

```
TypeError: Cannot read property 'toLowerCase' of undefined
    at ReactDOMServerRenderer.renderDOM (/Users/lukasborawski/Dev/web-client/node_modules/react-dom/cjs/react-dom-server.node.development.js:2304:27)
...
```

```
"react": "^16.1.1",
"react-dom": "^16.2.0",
```

Thx for help.
didWarnAboutUndefinedDerivedState[componentName] = true;
            }
          }
        }
        if (partialState != null) {
          inst.state = Object.assign({}, inst.state, partialState);
        }
      }
    } else {
      if (__DEV__) {
        if (
          Component.prototype &&
          typeof Component.prototype.render === 'function'
        ) {
          const componentName = getComponentName(Component) || 'Unknown';
          if (!didWarnAboutBadClass[componentName]) {
            warning(
              false,
              "The <%s /> component appears to have a render method, but doesn't extend React.Component. " +
                'This is likely to cause errors. Change %s to extend React.Component instead.',
              componentName,
              componentName,
            );
            didWarnAboutBadClass[componentName] = true;
          }
        }
      }
      inst = Component(element.props, publicContext, updater);
      if (inst == null || inst.render == null) {
        child = inst;