This message is a reminder that Fedora 28 is nearing its end of life.
On 2019-May-28 Fedora will stop maintaining and issuing updates for
Fedora 28. It is Fedora's policy to close all bug reports from releases
that are no longer maintained. At that time this bug will be closed as
EOL if it remains open with a Fedora 'version' of '28'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 28 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

This bug appears to have been reported against 'rawhide' during the Fedora 31 development cycle.
Changing version to '31'.

This bug appears to have been reported against 'rawhide' during the Fedora 31 development cycle.
Changing version to 31.

clamav-0.101.5-1.fc31 has been pushed to the Fedora 31 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2019-1543eae191

clamav-0.101.5-1.fc30 has been pushed to the Fedora 30 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2019-dcbfe89e39

clamav-0.101.5-1.el7 has been pushed to the Fedora EPEL 7 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2019-d6b0a398c2

clamav-0.101.5-1.el8 has been pushed to the Fedora EPEL 8 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2019-52445f11c2

clamav-0.101.5-1.fc29 has been pushed to the Fedora 29 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2019-ce438e7857

clamav-0.101.5-1.fc30 has been pushed to the Fedora 30 stable repository. If problems still persist, please make note of it in this bug report.

clamav-0.101.5-1.fc31 has been pushed to the Fedora 31 stable repository. If problems still persist, please make note of it in this bug report.

I still don't see any json data in clamscan output:

[ondrejj@work ~]$ rpm -q clamav
clamav-0.101.5-1.fc31.x86_64
[ondrejj@work ~]$ clamscan --gen-json /bin/ls
/bin/ls: OK

----------- SCAN SUMMARY -----------
Known viruses: 6794126
Engine version: 0.101.5
Scanned directories: 0
Scanned files: 1
Infected files: 0
Data scanned: 0.15 MB
Data read: 0.15 MB (ratio 1.00:1)
Time: 10.705 sec (0 m 10 s)
[ondrejj@work ~]$

Created attachment 1642024 [details]
0001-1631525-enable-libjson-Enables-libjson.patch

I checked this report and I made the pacth in attachment , but nothing changed. 
libjson is enabled we are missing something ... 

Thank you

Well, --gen-json is definitely "enabled", otherwise specifying --gen-json would produce:

!Can't generate json (gen-json). libjson-c dev library was missing or misconfigured when ClamAV was built.

Apparently output is only generate in combination with --debug and for specific files: "some office, pdf, or pe file"

see https://blog.clamav.net/2014/11/intro-to-collection-and-analysis-of.html

For a pdf file I got:

LibClamAV debug: { "Magic": "CLAMJSONv0", "RootFileType": "CL_TYPE_PDF", "FileType": "CL_TYPE_PDF", "FileSize": 64347, "FileMD5": "d7146c1a9cee064ead503f88a44f0b44", "PDFStats": { "PDFVersion": "1.3", "ObjectsWithoutDictionaries": [ 5, 11, 17, 7, 20, 26, 29, 31, 34, 35, 36, 35, 36, 36 ], "IncorrectPagesCount": true, "Producer": "Mac OS X 10.10.1 Quartz PDFContext", "ModificationDate": "D:20141210181337Z00'00'", "CreationDate": "D:20141210181337Z00'00'", "DeflateObjectCount": 6, "PageCount": 1 }, "ContainedObjects": [ { "FileType": "CL_TYPE_TEXT_ASCII", "FileSize": 170948, "FileMD5": "14f2991dfacb79bcdfaec7a76c5221b8" }, { "FileType": "CL_TYPE_TEXT_ASCII", "FileSize": 7079, "FileMD5": "bd3d689960efd7e41c1404afe8b78584" }, { "FileType": "CL_TYPE_BINARY_DATA", "FileSize": 1960, "FileMD5": "0d258bad36b64cebfb9e6826c3ed5037" }, { "FileType": "CL_TYPE_BINARY_DATA", "FileSize": 16392, "FileMD5": "5ceac6c32776184c508bb9ef48b3f7ca" }, { "FileType": "CL_TYPE_TEXT_ASCII", "FileSize": 342, "FileMD5": "021b9e6faf9b389d61e045e1f9194b14" }, { "FileType": "CL_TYPE_BINARY_DATA", "FileSize": 2228, "FileMD5": "cc787337be3ddd46f72bd4768fdb2291" }, { "FileType": "CL_TYPE_BINARY_DATA", "FileSize": 8116, "FileMD5": "1bdaa02cfa95c0dc8bfb75ce1d66bfa0" } ] }

Lets close with fixed, we added libjson-c-devel to the spec file