Hi!

I noticed that after update of Mediawiki to 1.28.2 I got these error

Cite error: Invalid <references> tag; parameter "group" is allowed only. Use < referencs/>, or < references/> SANtosito (talk) 19:54, 18 July 2017 (UTC)

Yes, this error was added nearly a decade ago to help editors fix it when they add <references/> with an invalid parameter; you have to remove the wrong parameter from the wikitext for it to go away.

Did you upgrade a very old version of the Cite extension? Jdforrester (WMF) (talk) 22:19, 18 July 2017 (UTC)

Don't know if it'll help, but I was getting the same error. In my case, the problem was that the Template:Reflist page had been revised. The only way I was able to fix the error was to revert the template to the revision before the updated version replaced it. Let me know how it goes! Bttfvgo (talk) 20:55, 27 July 2017 (UTC)

Here's the version that works:

<div class="reflist <!--
 -->{{#if: {{{1|}}}
    | columns {{#iferror: {{#ifexpr: {{{1|1}}} > 1 }}
      | references-column-width 
      | references-column-count references-column-count-{{#if:1|{{{1}}}}} }}
    | {{#if: {{{colwidth|}}}
      | references-column-width }} }}" style="<!--
 -->{{#if: {{{1|}}}
    | {{#iferror: {{#ifexpr: {{{1|1}}} > 1 }}
      | {{column-width|{{#if:1|{{{1}}}}}}}
      | {{column-count|{{#if:1|{{{1}}}}}}} }}
    | {{#if: {{{colwidth|}}}
      | {{column-width|{{{colwidth}}}}} }} }} list-style-type: <!--
 -->{{{liststyle|{{#switch: {{{group|}}}
    | upper-alpha
    | upper-roman
    | lower-alpha
    | lower-greek
    | lower-roman = {{{group}}}
    | #default = decimal}}}}};">
{{#tag:references|{{{refs|}}}|group={{{group|}}}}}</div><noinclude>
{{Documentation}}
</noinclude>

...and here is the only that starting causing the error. The "check for unknown parameters" caused the reflist to fail. At least it did in my case.

<div class="reflist <!--
 -->{{#if: {{{1|}}} {{{colwidth|}}}
    | columns references-column-width
	}}" style="<!--
 -->{{#if: {{{1|}}}
    | {{#iferror: {{#ifexpr: {{{1|1}}} > 1 }}
      | {{column-width|1={{{1}}}}}
      | {{#switch:{{{1|}}}|1=|2={{column-width|1=30em}}|#default={{column-width|1=25em}}}} }}
    | {{#if: {{{colwidth|}}}
      | {{column-width|1={{{colwidth}}}}} }} }} list-style-type: <!--
 -->{{{liststyle|{{#switch: {{{group|}}}
    | upper-alpha
    | upper-roman
    | lower-alpha
    | lower-greek
    | lower-roman = {{{group}}}
    | #default = decimal}}}}};">
{{#tag:references|{{{refs|}}}|group={{{group|}}}|responsive={{#if:{{{1|}}}{{{colwidth|}}}|0|1}}}}</div>{{#invoke:Check for unknown parameters|check|unknown={{main other|[[Category:Pages using reflist with unknown parameters|_VALUE_{{PAGENAME}}]]}}|preview=Page using [[Template:Reflist]] with unknown parameter "_VALUE_"|ignoreblank=y| 1 | colwidth | group | liststyle | refs }}<noinclude>
{{Documentation}}
</noinclude>

Hope this helps! Bttfvgo (talk) 20:59, 27 July 2017 (UTC)

Thanks!

I solved it by updating Extension:Cite to the newest one, everything works perfect now! SANtosito (talk) 22:42, 27 July 2017 (UTC)