When is a Delaware interlocutory certification application due?

Ordinarily serve and file the application for interlocutory certification in the trial court within ten days after entry of the challenged order. Rule 42(c)(i) permits a longer period allowed by the trial court for good cause. Certification is not Supreme Court acceptance.

Responsible actor. The party seeking certification of an interlocutory appeal.

Obtain the entered interlocutory order.

Address the Rule 42(b) substantial-issue and exceptional-review criteria.

Read any trial-court order changing the application period.

Use actual order entry and the ordinary ten-day component without a trial-court order allowing longer. Establish that the application concerns the Rule 42 interlocutory-review procedure.

1. Entry of the trial court interlocutory order sought to be reviewed
2. Exclude the established event day and count the stated component under Rule 11(a). No participant service addition is applied to this nonservice event.
3. Serve and file the certification application in the trial court and concurrently deliver its copy to the trial judge. Follow that trial court’s filing rules and preserve proof of all three acts.

Rule 11(a) excludes the event day. A prescribed period below seven days excludes intermediate Saturdays, Sundays and legal holidays. Seven days and longer count those intermediate days. A final Saturday, Sunday, legal holiday or actual Clerk closure receives the stated next-open-day treatment. A backward five-day motion component counts earlier eligible days to preserve its required lead. Do not apply the separate Chancery or Superior Court eleven-day threshold.

The 2026 named calendar follows the Court’s published statewide holidays. The 2027 dates are projections of 1 Del. C. § 501 and its fixed-holiday observation rule. December 31, 2027 is the observed New Year holiday for Saturday, January 1, 2028. These dates do not confirm future amendments, Governor or Chief Justice appointments or actual additional closures. Sussex Return Day afternoon is not treated as a statewide full-day Supreme Court closure. Review any actual additional closure separately.

Rule 42(a) directs computation under Supreme Court Rule 11. Rule 11(c) adds three days to a participant’s prescribed service-triggered period for mail or eFiling before final-day treatment. Personal service adds none. Establish effective service under the actual trial court’s procedures. The Supreme Court’s Rule 10 paper procedures do not automatically determine service below. Court acts and entry-based periods receive no participant service addition.

Reviewed coverage uses the retained Supreme Court compilation current through February 2, 2026, for established events on or after that compilation boundary and final dates through December 31, 2027. The index label is not a new effective date for every civil rule. Historical events, backward periods crossing that boundary, later dates, changed orders and actual additional closures require separate review. No computed or paid date is supplied for an input outside that coverage. This boundary does not establish that an actual act is late.

Fictitious example

Fictitious established current-edition event. Personal service where the period runs from service. No altered order or additional closure.

Fictitious established facts. The example does not establish applicability, actual service, completed filing, an extension, entitlement or a special closure. Use actual order entry and the ordinary ten-day component without a trial-court order allowing longer. Establish that the application concerns the Rule 42 interlocutory-review procedure.

Ten-day calendar component

Rule 42(a) uses Rule 11 computation. Ten days is not below seven, so intermediate weekends and legal holidays count.

Trial-court filing boundary

This application is filed below. The Supreme Court’s ordinary eFiling cutoff does not automatically establish the trial court’s cutoff.

Separate Supreme Court notice

Rule 42(d)(i) also requires the Supreme Court notice within thirty days after the interlocutory order’s entry. Do not wait for certification if that would miss the notice period.

Participant service and Court acts

Rule 42(a) directs computation under Supreme Court Rule 11. Rule 11(c) adds three days to a participant’s prescribed service-triggered period for mail or eFiling before final-day treatment. Personal service adds none. Establish effective service under the actual trial court’s procedures. The Supreme Court’s Rule 10 paper procedures do not automatically determine service below. Court acts and entry-based periods receive no participant service addition.

Compilation and calendar coverage

Reviewed coverage uses the retained Supreme Court compilation current through February 2, 2026, for established events on or after that compilation boundary and final dates through December 31, 2027. The index label is not a new effective date for every civil rule. Historical events, backward periods crossing that boundary, later dates, changed orders and actual additional closures require separate review. No computed or paid date is supplied for an input outside that coverage. This boundary does not establish that an actual act is late.

• Use actual order entry and the ordinary ten-day component without a trial-court order allowing longer. Establish that the application concerns the Rule 42 interlocutory-review procedure.
• The stated component does not obtain an extension, establish completed acts or decide an excluded procedural branch.

• Obtain the entered interlocutory order.
• Address the Rule 42(b) substantial-issue and exceptional-review criteria.
• Read any trial-court order changing the application period.
• Rule 42(a) uses Rule 11 computation. Ten days is not below seven, so intermediate weekends and legal holidays count.
• This application is filed below. The Supreme Court’s ordinary eFiling cutoff does not automatically establish the trial court’s cutoff.
• Rule 42(d)(i) also requires the Supreme Court notice within thirty days after the interlocutory order’s entry. Do not wait for certification if that would miss the notice period.
• This act belongs in the trial court. Rule 42(c)(v) requires concurrent delivery of the application or response copy to the trial judge, in addition to service and filing. Establish the actual trial court’s electronic or paper cutoff, time zone, service procedure, case order and completed receipts. The Supreme Court’s 5 p.m. ordinary eFiling cutoff does not automatically govern a filing below.