You have 3 things in the chart: the x-axis; the y-axis; and, the series. The legend applies to the series not the axis.
Please share your SPL and clarify what you want the legend to show
Sort x axis
The legend is in the order of the series in the table. Chart tries to be helpful by putting these in a sorted order. In order to work against this, you have to do a couple of tricks. Try this:
| chart count(Device_ID) over latestversion by Final useother=f
| untable latestversion Final count
| where count > 0
| eval Final=latestversion."!".Final
| xyseries latestversion Final count
| transpose 0 column_name=Final header_field=latestversion
| eval Final=mvindex(split(Final,"!"),1)
| transpose 0 column_name=latestversion header_field=Final
Thanks. But now legend values not in sorted order. It is 2020, 2021, 2020 etc..But we need 2020 2020 2021.
| chart count(Device_ID) over latestversion by Final useother=f
| untable latestversion Final count
| where count > 0
| eval latestversion=Final."!".latestversion
| xyseries latestversion Final count
| eval latestversion=mvindex(split(latestversion,"!"),1)
Thank you. It is working perfectly