darth_fader

This deprecation started on JDK V9. JasperReports library (and JasperServer) are compatible with specific versions of Java, and so if you compiled the report in JDK 8 you'd eliminate this issue.
Potential solutions include:
1. install JDK 8 and configuring your environment to use that rather than 13
2. update the version of JasperReports/Server you're using - assuming the latest libraries are compatible with JDK 13, I'm a few versions behind and so I'm not sure what's compatible with what
3. ignore it for now - this type of deprecated functionality is not likely to cause problems - that type of casting is so widely used, and the integer functionality so basic, that you likely won't have any problems with this. If your project can't tolerate these warnings, you'll have to work through one of the first two options.
 

If you're working with an older version of Jasper Server (6.2.x or older) you'll need to enable using stored procedures - steps are detailed here:
https://community.jaspersoft.com/wiki/how-execute-ms-sql-stored-procedure-jasperreports-server
If you're working with version 6.3 plus, no changes are needed. If this doesn't address the issue you're expriencing, post your jrxml. Is this the first report resource you're publishing that references a stored proc?

The <property name="net.sf.jasperreports.export.xls.auto.fit.column" value="true"/> should be functional, but it looks like it has to go on the reportElement level, so you'd have to place it on each column in your table. Curious to see if this works for you.

the table component is primarily column centric; crosstabs are worth looking into as they group by rows first and I don't think they require column groups. alternatively, here's a functional approach that uses a subreport:
 
https://stackoverflow.com/questions/34171805/how-to-merge-cells-in-same-column-apply-rowspan

No, but can you send along the url you're using and the root folder name containing your reports? I can see if anything's wrong there. You're successfully making the request might just be something slightly wrong with the url

Although the following posts are slightly dated, I think it's still applicable for inline svgs
Show how to use proper renderer for inline svgs:
http://community.jaspersoft.com/questions/826134/how-use-svg-information-jasper-report
and more info on svg rendering in general:
http://community.jaspersoft.com/questions/525861/how-use-svg-jasperreports
http://community.jaspersoft.com/wiki/how-add-svg-image-your-report-jrxml

You can add an attribute to each user in your jasperserver installation that sets a value in the JDBC connection dynamically based on user. For example, you can set properties in the jdbc connection based on those attributes. In this way you can change the datasource based on the user. Again, this is all done at the jasperserver level.
There is a reference that also accomplishes something similar via spring, but I don't think it's necessary.
http://community.jaspersoft.com/wiki/switching-datasource-based-user
 

Put this in your text field expression:
 
org.joda.time.format.DateTimeFormat.forPattern("MM/dd/yyyy").print(new org.joda.time.DateTime($F{dob}).withZone(org.joda.time.DateTimeZone.forID("UTC")))
 
There may be a way to preserve the format attribute on the text field tag, if that's a necessity let me know
 
 

The table component is the way to do this; otherwise you're dealing with a classic absolute positioning issue. If you can't convert to a table and this is a must have requirement, look into a pure java solution. Also there is Velocity/Jrxml dynamic template approach.

I keep both JasperSoft Studio and iReport handy because they both have advantages/benefits that the other is missing. I think of them as two separate tools. The shame is that iReport is being put to pasture and with it will go alot of great functionality.
No migration tool that I'm aware of.