Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
PCI Express
Table title:
History and revisions
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=2 > PCI Express version </th><th colspan=1 rowspan=2 > Introduced </th><th colspan=1 rowspan=2 > Line code </th><th colspan=1 rowspan=2 > Transfer rate </th><th colspan=5 rowspan=1 > Throughput </th></tr>
<tr> <th colspan=1 rowspan=1 > ×1 </th><th colspan=1 rowspan=1 > ×2 </th><th colspan=1 rowspan=1 > ×4 </th><th colspan=1 rowspan=1 > ×8 </th><th colspan=1 rowspan=1 > ×16 </th></tr>
<tr> <td colspan=1 rowspan=1 > 1.0 </td><td colspan=1 rowspan=1 > 2003 </td><td colspan=1 rowspan=1 > 8b/10b </td><td colspan=1 rowspan=1 > 2.5 GT/s </td><td colspan=1 rowspan=1 > 250 MB/s </td><td colspan=1 rowspan=1 > 0.50 GB/s </td><td colspan=1 rowspan=1 > 1.0 GB/s </td><td colspan=1 rowspan=1 > 2.0 GB/s </td><td colspan=1 rowspan=1 > 4.0 GB/s </td></tr>
<tr> <td colspan=1 rowspan=1 > 2.0 </td><td colspan=1 rowspan=1 > 2007 </td><td class="highlighted"  colspan=1 rowspan=1 > 8b/10b </td><td colspan=1 rowspan=1 > 5.0 GT/s </td><td colspan=1 rowspan=1 > 500 MB/s </td><td colspan=1 rowspan=1 > 1.0 GB/s </td><td colspan=1 rowspan=1 > 2.0 GB/s </td><td colspan=1 rowspan=1 > 4.0 GB/s </td><td colspan=1 rowspan=1 > 8.0 GB/s </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 3.0 </td><td colspan=1 rowspan=1 > 2010 </td><td class="highlighted"  colspan=1 rowspan=1 > 128b/130b </td><td colspan=1 rowspan=1 > 8.0 GT/s </td><td colspan=1 rowspan=1 > 984.6 MB/s </td><td colspan=1 rowspan=1 > 1.97 GB/s </td><td colspan=1 rowspan=1 > 3.94 GB/s </td><td colspan=1 rowspan=1 > 7.88 GB/s </td><td colspan=1 rowspan=1 > 15.8 GB/s </td></tr>
<tr> <td colspan=1 rowspan=1 > 4.0 </td><td colspan=1 rowspan=1 > 2017 </td><td colspan=1 rowspan=1 > 128b/130b </td><td colspan=1 rowspan=1 > 16.0 GT/s </td><td colspan=1 rowspan=1 > 1969 MB/s </td><td colspan=1 rowspan=1 > 3.94 GB/s </td><td colspan=1 rowspan=1 > 7.88 GB/s </td><td colspan=1 rowspan=1 > 15.75 GB/s </td><td colspan=1 rowspan=1 > 31.5 GB/s </td></tr>
<tr> <td colspan=1 rowspan=1 > 5.0 </td><td colspan=1 rowspan=1 > expected in Q1 2019 </td><td colspan=1 rowspan=1 > 128b/130b </td><td colspan=1 rowspan=1 > 32.0 GT/s </td><td colspan=1 rowspan=1 > 3938 MB/s </td><td colspan=1 rowspan=1 > 7.88 GB/s </td><td colspan=1 rowspan=1 > 15.75 GB/s </td><td colspan=1 rowspan=1 > 31.51 GB/s </td><td colspan=1 rowspan=1 > 63.0 GB/s </td></tr>
</table>
Question:
How does PCI Express 3.0 line code different from the 2.0 version? 
Answer:
PCI Express 3.0 upgrades the encoding scheme to 128b/130b from the previous 8b/10b encoding.