Letter Amendment, dated November 6, 2018, to Membership Interest Purchase Agreement, dated as of May 4, 2018, by and among Old Ironsides Fund II-A Portfolio Holding Company, LLC, Old Ironsides Fund II-B Portfolio Holding Company, LLC, and Carbon Energy Corporation

Exhibit 10.1

November 6, 2018

Old Ironsides Energy

10 St. James Avenue, 19^th Floor

Boston, Massachussetts 02116

Attention: Scott Carson

Gentlemen:

In accordance with Section 9.3 of the Purchase Agreement, when executed by you below, this letter shall confirm the agreement between Sellers and Purchaser and amend the Purchase Agreement in the following respects:

(1) In Section 9.1(a)(iv), the first phrase, which currently reads

“by the Purchaser upon written notice to Sellers given at any time on or after November 6, 2018 (the “Purchaser’s Outside Date”);”

is hereby amended to read as follows:

“by the Purchaser upon written notice to Sellers given at any time on or after November 30, 2018 (the “Purchaser’s Outside Date”);”

(2) In Section 9.1(a)(v), the first phrase, which currently reads

“by Sellers upon written notice to Purchaser given at any time on or after November 6, 2018 (the “Sellers’ Outside Date”);”

is hereby amended to read as follows:

“by Sellers upon written notice to Purchaser given at any time on or after November 30, 2018 (the “Sellers’ Outside Date”);”

Otherwise the Purchase Agreement shall remain in full force and effect, in accordance with its existing terms and provisions.

This agreement amending the Purchase Agreement may be executed in any number of counterparts, and each counterpart hereof shall be effective as to each party that executes the same whether or not all parties execute the same counterpart. If counterparts of this agreement are executed, the signature pages from various counterparts may be combined into one composite instrument for all purposes. All counterparts together shall constitute only one agreement, but each counterpart shall be considered an original. This agreement may be executed and delivered by exchange by email of PDF copies showing the signatures of the parties, and those PDF copies showing the signatures of the parties will constitute originally signed copies of the same agreement requiring no further execution.

[Signatures Page Follows]

AGREED AND ACCEPTED as of the date first written above.